Updated Comfignat to version 1.1.version_1.4

7 files changed, 759 insertions, 226 deletions

diff --git a/INSTALL b/INSTALL
index 7efb59b..c94f0be 100644
--- a/INSTALL
+++ b/INSTALL
@@ -5,7 +5,8 @@ Requirements
 ------------
 
 These instructions assume a Unix-like system with the GNAT tools and GNU Make.
-The makefiles may not work with other Make clones than GNU Make. If you can't
+The makefiles may not work with other clones and forks of Make. Use GNU Make if
+possible; it is sometimes available as "gmake" on non-GNU systems. If you can't
 use Make you will need to manually preprocess some GNAT project files with
 Gnatprep. If you have another Ada compiler than GNAT, then the included build
 system will probably not work and you should do whatever that compiler requires
@@ -24,7 +25,7 @@ The simplest way to build and install System_Log is:
 
  2: Run "make install" to copy the files to the default locations. You will
     probably need root privileges if you install to the default locations.
-    
+
 
 Testing
 -------
@@ -42,59 +43,73 @@ the Gnatprep command line if you can't use Make. The following Make variables
 are relevant during the build:
 
  dirgpr
-    The filename of the directory project, if your system has one and you want
-    to install to the directories it specifies. A directory project is a GNAT
-    project file that defines directory variables for use by other project
-    files. Multilib support requires a directory project that can refer to
-    different directories depending on the target architecture. A directory
+    The filename of the directories project, if your system has one and you
+    want to install to the directories it specifies. A directories project is a
+    GNAT project file that defines directory variables for use by other project
+    files. Multiarch support requires a directories project that can refer to
+    different directories depending on the target architecture. A directories
     project overrides some but not all of the directory variables listed below.
 
+ relocatable_package
+    If relocatable_package is true and no directories project is provided, then
+    the project file that will be installed with the library will be configured
+    with relative pathnames so that the installed directory tree as a whole can
+    be moved to another location in the filesystem without breaking the project
+    file. Default: false
+
  prefix
     A prefix used in the default values of the directory variables listed
     below. Default: /usr/local
 
  exec_prefix
-    A prefix used in the default locations for architecture-specific files.
-    Default: <prefix>
+    A prefix used in the default locations for programs, binary libraries and
+    other architecture-specific files. Default: <prefix>
 
  datarootdir
     The root of the directory tree for read-only architecture-independent data
     files. Default: <prefix>/share
 
  includedir
-    The directory for source files that are needed for compilation of code that
-    uses the library, used only if no directory project is provided.
+    The top-level directory for source files to be used in the compilation of
+    software using libraries, used only if no directories project is provided.
     Default: <prefix>/include
 
  libdir
-    The directory for binary libraries and other architecture-specific files,
-    used only if no directory project is provided. Default: <exec_prefix>/lib
+    The directory for binary libraries to be used by other software, and the
+    top-level directory for other architecture-specific files, used only if no
+    directories project is provided. Default: <exec_prefix>/lib
 
  gprdir
-    The directory for GNAT project files. Default: <datarootdir>/gpr
+    The directory for GNAT project files to be used in the building of software
+    using libraries. If you set this to a directory that GPRbuild and Gnatmake
+    don't search by default, then you will need to add it to the project search
+    path when using this library, for example through the environment variable
+    GPR_PROJECT_PATH. Default: <datarootdir>/gpr
 
 If you want to install to a staging directory from which the files will later
 be copied to their final locations, then set DESTDIR to the staging directory.
 All the other directory variables shall be the final locations. Unlike the
 variables listed above, DESTDIR is effective in the installation step.
 
-The following preprocessor symbols are defined by the makefiles, and may be
-defined manually if Make can't be used:
+The following preprocessor symbols are used when the project files are
+preprocessed. They are derived from the Make variables above when the makefiles
+invoke Gnatprep. You may need to define them if you run Gnatprep manually.
 
- Directory_GPR
-    The filename of the directory project, if any; corresponding to dirgpr.
+ Directories_GPR
+    The filename of the directories project, if any; corresponding to dirgpr.
 
- Directory_Project
-    The name of the directory project, if any. This is supposed to be the
+ Directories_Project
+    The name of the directories project, if any. This is supposed to be the
     filename without a path or a suffix.
 
  Prefix
  Exec_Prefix
  Includedir
  Libdir
-    These correspond to the like-named Make variables.
+    These correspond to the like-named Make variables. The same defaults as
+    above will be used if the symbols are undefined.
+
 
-    
 Build Tools and Options
 -----------------------
 
@@ -126,11 +141,18 @@ options are passed to them:
     A space-separated list of options to be passed to the compiler when
     compiling Ada code, used only if GNATFLAGS is undefined.
 
+ GNATBINDFLAGS
+    A space-separated list of options to be passed to Gnatbind, used only if
+    GNATFLAGS is undefined and only when binding the demo program.
+
+ GNATLINKFLAGS
+    A space-separated list of options to be passed to Gnatlink, used only if
+    GNATFLAGS is undefined, only if the builder is Gnatmake, and only when
+    linking the demo program.
+
  LDFLAGS
     A space-separated list of options to be passed to the linker, used only if
-    GNATFLAGS is undefined. (Unfortunately neither GPRbuild nor Gnatmake can
-    forward command line options to the linker when linking a shared library,
-    so LDFLAGS affects only the demo program.)
+    GNATFLAGS is undefined and only when linking the demo program.
 
 
 Copyright of This File
diff --git a/Makefile b/Makefile
index 5ae722c..ac27a04 100644
--- a/Makefile
+++ b/Makefile
@@ -15,4 +15,4 @@ test: build build_test_system_log.gpr
 	${build_GPR}
 
 clean::
-	rm -f test_system_log
+	rm -f "${builddir}/test_system_log"
diff --git a/build_test_system_log.gpr b/build_test_system_log.gpr
index 046c929..b88047a 100644
--- a/build_test_system_log.gpr
+++ b/build_test_system_log.gpr
@@ -14,7 +14,7 @@ standard project Build_Test_System_Log is
    for Main        use ("test_system_log");
    for Source_Dirs use ("test");
    for Object_Dir  use Comfignat.Objdir;
-   for Exec_Dir    use ".";
+   for Exec_Dir    use Comfignat.Builddir;
 
    package Binder is
       for Default_Switches ("Ada") use ("-shared");
diff --git a/comfignat.gpr.gp b/comfignat.gpr.gp
new file mode 100644
index 0000000..e334f00
--- /dev/null
+++ b/comfignat.gpr.gp
@@ -0,0 +1,279 @@
+-- Comfignat configuration variables for GNAT project files
+-- Copyright 2013 B. Persson, Bjorn@Rombobeorn.se
+--
+-- This material is provided as is, with absolutely no warranty expressed
+-- or implied. Any use is at your own risk.
+--
+-- Permission is hereby granted to use or copy this project file
+-- for any purpose, provided the above notices are retained on all copies.
+-- Permission to modify the code and to distribute modified code is granted,
+-- provided the above notices are retained, and a notice that the code was
+-- modified is included with the above copyright notice.
+
+
+-- This file is part of Comfignat – common, convenient, command-line-controlled
+-- compile-time configuration of software built with the GNAT tools. For more
+-- information about Comfignat, see http://www.Rombobeorn.se/Comfignat/.
+
+
+-- This project file defines directory variables for use in build-controlling
+-- project files. It is not to be installed on the target system.
+--
+-- Normally the preprocessing of this file will be controlled by comfignat.mk,
+-- which will make it import the directories project if one is provided. It can
+-- also be preprocessed manually if Make cannot be used for some reason. There
+-- are defaults that will be used if no preprocessor symbols are defined.
+
+
+#if Directories_GPR'Defined then
+   with $Directories_GPR;
+#end if;
+
+abstract project Comfignat is
+
+   #if not Invoked_By_Makefile'Defined then
+
+      --
+      -- These variables are used in constructing the default values of the
+      -- directory variables below. They're only needed when this file is
+      -- preprocessed manually.
+      --
+
+      #if Prefix'Defined then
+         Prefix := $Prefix;
+      #else
+         Prefix := "/usr/local";
+      #end if;
+      -- Prefix is used in the default locations for almost all files.
+
+      #if Exec_Prefix'Defined then
+         Exec_Prefix := $Exec_Prefix;
+      #else
+         Exec_Prefix := Prefix;
+      #end if;
+      -- Exec_Prefix is used in the default locations for programs, binary
+      -- libraries and other architecture-specific files.
+
+      #if Datarootdir'Defined then
+         Datarootdir := $Datarootdir;
+      #else
+         Datarootdir := Prefix & "/share";
+      #end if;
+      -- Datarootdir is the root of the directory tree for read-only
+      -- architecture-independent data files.
+
+      #if Localstatedir'Defined then
+         Localstatedir := $Localstatedir;
+      #else
+         Localstatedir := Prefix & "/var";
+      #end if;
+      -- Localstatedir is the root of the directory tree for data files that
+      -- programs modify while they run.
+
+   #end if;
+
+
+   --
+   -- The following variables may be compiled into programs or libraries to
+   -- tell them where to find or write different kinds of files at run time.
+   -- Most of the directory names are relative to Bindir if the software was
+   -- configured as a relocatable package. Otherwise they are absolute
+   -- pathnames.
+   --
+
+   -- Programs that can be run from a command prompt are in Bindir. This is
+   -- normally the same directory that the program itself is in, so this
+   -- variable is probably of little use at run time.
+   #if Bindir'Defined then
+      Bindir := $Bindir;
+   #else
+      Bindir := Exec_Prefix & "/bin";
+   #end if;
+
+   -- Programs that are intended to be run by other programs rather than by
+   -- users are under Libexecdir.
+   #if Libexecdir'Defined then
+      Libexecdir := $Libexecdir;
+   #else
+      Libexecdir := Exec_Prefix & "/libexec";
+   #end if;
+
+   -- Idiosyncratic read-only architecture-independent data files are under an
+   -- application-specific subdirectory of Datadir.
+   #if Datadir'Defined then
+      Datadir := $Datadir;
+   #else
+      Datadir := Datarootdir;
+   #end if;
+
+   -- Host-specific configuration files are under Sysconfdir.
+   #if Sysconfdir'Defined then
+      Sysconfdir := $Sysconfdir;
+   #else
+      Sysconfdir := Prefix & "/etc";
+   #end if;
+
+   -- Idiosyncratic variable data files shall be kept under an application-
+   -- specific subdirectory of Statedir.
+   #if Statedir'Defined then
+      Statedir := $Statedir;
+   #else
+      Statedir := Localstatedir & "/lib";
+   #end if;
+
+   -- Cached data files that the application can regenerate if they are deleted
+   -- shall be kept under an application-specific subdirectory of Cachedir.
+   #if Cachedir'Defined then
+      Cachedir := $Cachedir;
+   #else
+      Cachedir := Localstatedir & "/cache";
+   #end if;
+
+   -- Log files shall be written under Logdir.
+   #if Logdir'Defined then
+      Logdir := $Logdir;
+   #else
+      Logdir := Localstatedir & "/log";
+   #end if;
+
+   -- Source files to be used in the compilation of software using libraries
+   -- are under Includedir.
+   #if Includedir'Defined then
+      Includedir := $Includedir;
+   #else
+      Includedir := Prefix & "/include";
+   #end if;
+
+   -- Binary libraries and other architecture-specific files are under Libdir.
+   #if Libdir'Defined then
+      Libdir := $Libdir;
+   #else
+      Libdir := Exec_Prefix & "/lib";
+   #end if;
+
+   -- GNAT project files are under GPRdir.
+   #if GPRdir'Defined then
+      GPRdir := $GPRdir;
+   #else
+      GPRdir := Datarootdir & "/gpr";
+   #end if;
+
+   -- Locale-specific message catalogs are under Localedir.
+   #if Localedir'Defined then
+      Localedir := $Localedir;
+   #else
+      Localedir := Datarootdir & "/locale";
+   #end if;
+
+   -- Documentation in the Man format is under Mandir.
+   #if Mandir'Defined then
+      Mandir := $Mandir;
+   #else
+      Mandir := Datarootdir & "/man";
+   #end if;
+
+   -- Documentation in the Info format is in Infodir.
+   #if Infodir'Defined then
+      Infodir := $Infodir;
+   #else
+      Infodir := Datarootdir & "/info";
+   #end if;
+
+   -- Other documentation files are under an application-specific subdirectory
+   -- of Miscdocdir.
+   #if Miscdocdir'Defined then
+      Miscdocdir := $Miscdocdir;
+   #else
+      Miscdocdir := Datarootdir & "/doc";
+   #end if;
+
+   -- Small files that take part in describing the state of the system, and
+   -- that exist only while the program is running, such as process identifier
+   -- files and transient Unix-domain sockets, shall be created under
+   -- Runtimedir. (This is NOT the place for temporary files in general.)
+   #if Runtimedir'Defined then
+      Runtimedir := $Runtimedir;
+   #else
+      Runtimedir := "/run";
+   #end if;
+
+   -- Lock files that are used to prevent multiple programs from trying to
+   -- access a device or other resource at the same time shall be created under
+   -- Lockdir.
+   #if Lockdir'Defined then
+      Lockdir := $Lockdir;
+   #else
+      Lockdir := Runtimedir & "/lock";
+   #end if;
+
+
+   --
+   -- The following variables are for use in attributes to control where
+   -- generated files are placed.
+   --
+
+   -- Various generated files are kept in Builddir.
+   #if Builddir'Defined then
+      Builddir := $Builddir;
+   #else
+      Builddir := ".";
+   #end if;
+
+   -- Intermediate files produced during the build shall be kept in Objdir.
+   #if Objdir'Defined then
+      Objdir := $Objdir;
+   #else
+      Objdir := Builddir & "/obj";
+   #end if;
+
+   #if Directories_Project'Defined then
+      -- Put intermediate files for different architectures in subdirectories
+      -- where they won't conflict with each other. (This is useful especially
+      -- with binder files when they are packaged in debug information packages
+      -- for multiarch systems.)
+      Objdir := Objdir & "/" & $Directories_Project.Hardware_Platform;
+   #end if;
+
+   -- Files to be installed shall be placed under Stagedir instead of the root
+   -- directory. (This variable is unused by Comfignat when Make is used and no
+   -- directories project is provided.)
+   #if Stagedir'Defined then
+      Stagedir := $Stagedir;
+   #else
+      Stagedir := external("DESTDIR", "");
+   #end if;
+
+   -- Programs that can be run from a command prompt shall be installed in
+   -- Stage_Bindir.
+   #if Stage_Bindir'Defined then
+      Stage_Bindir := $Stage_Bindir;
+   #else
+      Stage_Bindir := Stagedir & Bindir;
+   #end if;
+
+   -- Programs that are only to be run by other programs, not by users, shall
+   -- be installed under Stage_Libexecdir.
+   #if Stage_Libexecdir'Defined then
+      Stage_Libexecdir := $Stage_Libexecdir;
+   #else
+      Stage_Libexecdir := Stagedir & Libexecdir;
+   #end if;
+
+   -- Source files needed for compiling code that uses a library shall be
+   -- installed under Stage_Includedir.
+   #if Stage_Includedir'Defined then
+      Stage_Includedir := $Stage_Includedir;
+   #else
+      Stage_Includedir := Stagedir & Includedir;
+   #end if;
+
+   -- Binary libraries shall be installed in Stage_Libdir.
+   -- ALI files shall be installed in a library-specific subdirectory of
+   -- Stage_Libdir.
+   #if Stage_Libdir'Defined then
+      Stage_Libdir := $Stage_Libdir;
+   #else
+      Stage_Libdir := Stagedir & Libdir;
+   #end if;
+
+end Comfignat;
diff --git a/comfignat.gpr.in b/comfignat.gpr.in
deleted file mode 100644
index 8212336..0000000
--- a/comfignat.gpr.in
+++ /dev/null
@@ -1,98 +0,0 @@
--- Comfignat configuration variables for GNAT project files
--- Copyright 2013 B. Persson, Bjorn@Rombobeorn.se
---
--- This material is provided as is, with absolutely no warranty expressed
--- or implied. Any use is at your own risk.
---
--- Permission is hereby granted to use or copy this project file
--- for any purpose, provided the above notices are retained on all copies.
--- Permission to modify the code and to distribute modified code is granted,
--- provided the above notices are retained, and a notice that the code was
--- modified is included with the above copyright notice.
-
-
--- This project file defines directory variables for use in build-controlling
--- project files. It is not to be installed on the target system.
---
--- Normally the preprocessing of this file will be controlled by comfignat.mk,
--- which will make it import the directory project if one is provided. It can
--- also be preprocessed manually if Make cannot be used for some reason. There
--- are defaults that will be used if no preprocessor symbols are defined.
-
-
-#if Directory_GPR'Defined then
-   with $Directory_GPR;
-#end if;
-
-abstract project Comfignat is
-
-   #if Objdir'Defined then
-      Objdir := $Objdir;
-   #else
-      Objdir := "build";
-   #end if;
-   -- Intermediate files produced during the build shall be kept in Objdir.
-
-   #if Directory_Project'Defined then
-      -- Put intermediate files for different architectures in subdirectories
-      -- where they won't conflict with each other. (This is useful especially
-      -- with binder files when they are packaged in debug information packages
-      -- for multiarch systems.)
-      Objdir := Objdir & "/" & $Directory_Project.Hardware_Platform;
-   #end if;
-
-   #if Stagedir'Defined then
-      Stagedir := $Stagedir;
-   #else
-      Stagedir := external("DESTDIR", "");
-   #end if;
-   -- Files to be installed shall be placed under Stagedir instead of the root
-   -- directory.
-
-   #if Prefix'Defined then
-      Prefix := $Prefix;
-   #else
-      Prefix := "/usr/local";
-   #end if;
-
-   #if Exec_Prefix'Defined then
-      Exec_Prefix := $Exec_Prefix;
-   #else
-      Exec_Prefix := Prefix;
-   #end if;
-
-   #if Bindir'Defined then
-      Bindir := $Bindir;
-   #else
-      Bindir := Exec_Prefix & "/bin";
-   #end if;
-   Stage_Bindir := Stagedir & Bindir;
-   -- Programs intended to be run by users shall be installed in Stage_Bindir.
-
-   #if Libexecdir'Defined then
-      Libexecdir := $Libexecdir;
-   #else
-      Libexecdir := Exec_Prefix & "/libexec";
-   #end if;
-   Stage_Libexecdir := Stagedir & Libexecdir;
-   -- Programs intended to be run by other programs rather than by users shall
-   -- be installed under Stage_Libexecdir.
-
-   #if Includedir'Defined then
-      Includedir := $Includedir;
-   #else
-      Includedir := Prefix & "/include";
-   #end if;
-   Stage_Includedir := Stagedir & Includedir;
-   -- Source files needed for compiling against a library shall be installed
-   -- under Stage_Includedir.
-
-   #if Libdir'Defined then
-      Libdir := $Libdir;
-   #else
-      Libdir := Prefix & "/lib";
-   #end if;
-   Stage_Libdir := Stagedir & Libdir;
-   -- Binary libraries shall be installed in Stage_Libdir.
-
-end Comfignat;
diff --git a/comfignat.mk b/comfignat.mk
index aea3103..07ae8d2 100644
--- a/comfignat.mk
+++ b/comfignat.mk
@@ -11,6 +11,11 @@
 # modified is included with the above copyright notice.
 
 
+# This file is part of Comfignat – common, convenient, command-line-controlled
+# compile-time configuration of software built with the GNAT tools. For more
+# information about Comfignat, see http://www.Rombobeorn.se/Comfignat/.
+
+
 # This file contains generic Make code. It is designed to be included by other
 # makefiles, called containing makefiles, which add information specific to the
 # project at hand. Builds are controlled by GNAT project files which import the
@@ -19,7 +24,7 @@
 # system. Usage projects and the Comfignat project will be preprocessed with
 # Gnatprep. (Build projects may also be preprocessed.)
 #
-# If a directory project is provided, then the project files will get the
+# If a directories project is provided, then the project files will get the
 # directory variables from there, otherwise the Make variables will be used.
 #
 # This file may not work with other Make clones than GNU Make. (Reusable Make
@@ -39,17 +44,28 @@ GNAT_BUILDER ?= gprbuild
 # If GNAT_BUILDER looks like it will invoke Gnatmake, then make the default
 # value of GNATFLAGS compatible with Gnatmake. Otherwise make it suitable for
 # building multi-language projects with GPRbuild.
-ifeq ($(findstring gnatmake,${notdir ${lastword ${GNAT_BUILDER}}}),)
-   GNATFLAGS ?= ${GNAT_BUILDER_FLAGS} \
-                -cargs:Ada ${ADAFLAGS} -cargs:C ${CFLAGS} \
-                -cargs:C++ ${CXXFLAGS} -cargs:Fortran ${FFLAGS} \
-                -largs ${LDFLAGS}
-else
-   GNATFLAGS ?= ${GNAT_BUILDER_FLAGS} -cargs ${ADAFLAGS} -largs ${LDFLAGS}
-endif
+GNATFLAGS ?= ${if ${findstring gnatmake, \
+                               ${notdir ${call mung_string,${GNAT_BUILDER}}}}, \
+                  ${GNAT_BUILDER_FLAGS} \
+                     -cargs ${ADAFLAGS} \
+                     -bargs ${GNATBINDFLAGS} \
+                     -largs ${GNATLINKFLAGS} ${LDFLAGS}, \
+                  ${GNAT_BUILDER_FLAGS} \
+                     -cargs:Ada ${ADAFLAGS} \
+                     -cargs:C ${CPPFLAGS} ${CFLAGS} \
+                     -cargs:C++ ${CPPFLAGS} ${CXXFLAGS} \
+                     -cargs:Fortran ${FFLAGS} \
+                     -bargs ${GNATBINDFLAGS} \
+                     -largs ${LDFLAGS}}
 
 # (DESTDIR is also supported.)
 
+# Containing makefiles may assign default values to the options variables
+# GNAT_BUILDER_FLAGS, ADAFLAGS, CPPFLAGS, CFLAGS, CXXFLAGS, FFLAGS,
+# GNATBINDFLAGS, GNATLINKFLAGS and LDFLAGS if they are undefined in the
+# environment, but should expect that users and distributions may override
+# those defaults.
+
 
 #
 # These variables should be overridden on the command line as needed, but will
@@ -57,72 +73,138 @@ endif
 #
 
 dirgpr =
-# dirgpr should be the filename of the directory project if there is one. It
-# becomes the Gnatprep symbols Directory_GPR and Directory_Project.
+# dirgpr should be the filename of the target system's directories project if
+# there is one. The Gnatprep symbols Directories_GPR and Directories_Project
+# will be derived from dirgpr, and project files will be configured to use the
+# directories project.
+
+relocatable_package = false
+# If relocatable_package is true, then directory variables in project files
+# will be configured with relative pathnames so that the installed directory
+# tree as a whole can be moved to another location in the filesystem without
+# breaking the project files.
+# dirgpr takes precedence over relocatable_package.
 
 prefix        = /usr/local
 exec_prefix   = ${prefix}
-bindir        = ${exec_prefix}/bin
-libexecdir    = ${exec_prefix}/libexec
 datarootdir   = ${prefix}/share
-datadir       = ${datarootdir}
-sysconfdir    = ${prefix}/etc
 localstatedir = ${prefix}/var
-includedir    = ${prefix}/include
-libdir        = ${exec_prefix}/lib
-gprdir        = ${datarootdir}/gpr
-localedir     = ${datarootdir}/locale
-mandir        = ${datarootdir}/man
-infodir       = ${datarootdir}/info
-# These are the directories where different kinds of files will be installed on
-# the target system. Some of these directory variables aren't used in this file
-# but may be needed in containing makefiles.
-
-builddir = build
+# These variables are used in constructing the default values of the directory
+# variables below.
+
+bindir     = ${exec_prefix}/bin
+libexecdir = ${exec_prefix}/libexec
+datadir    = ${datarootdir}
+sysconfdir = ${prefix}/etc
+statedir   = ${localstatedir}/lib
+cachedir   = ${localstatedir}/cache
+logdir     = ${localstatedir}/log
+includedir = ${prefix}/include
+libdir     = ${exec_prefix}/lib
+gprdir     = ${datarootdir}/gpr
+localedir  = ${datarootdir}/locale
+mandir     = ${datarootdir}/man
+infodir    = ${datarootdir}/info
+miscdocdir = ${datarootdir}/doc
+runtimedir = /run
+lockdir    = ${runtimedir}/lock
+# These are the directories where different kinds of files will be located on
+# the target system.
+
+builddir = ${CURDIR}
 objdir   = ${builddir}/obj
 stagedir = ${builddir}/stage
+# builddir is the build directory, which may be separate from the source tree.
 # Intermediate files produced during the build are kept in objdir. Files to be
-# installed are written to stagedir, and then copied to their destination in
+# installed are written under stagedir, and then copied to their destination in
 # the installation step.
 
-ifeq (${DESTDIR},)
-   install_cp_flags =
-else   
-   install_cp_flags = --preserve=timestamps
-endif
-# Timestamps are preserved when installation is done to a staging directory. 
+# Containing makefiles should avoid modifying the directory variables. Users
+# should be able to rely on these defaults.
+
+install_cp_flags = ${if ${DESTDIR},--preserve=timestamps}
+# Timestamps are preserved when installation is done to a staging directory.
 # This matters for files that aren't generated during the build but copied from
 # the source tree. Timestamps are not preserved when installation is done
-# directly to the target system, because that would change the timestamps of 
+# directly to the target system, because that would change the timestamps of
 # existing directories.
 
 
 #
-# Containing makefiles should assign or append to these variables as needed:
+# Containing makefiles may use these variables in their rules, but nothing
+# should modify them:
 #
 
-ifneq (${origin configured_files},file)
-   configured_files := ${basename ${wildcard *.in}}
-endif
-# configured_files is a list of files to be produced in the preprocessing step
-# at the beginning of the build. Containing makefiles may override it or append
-# additional filenames to it.
+srcdir := ${abspath ${dir ${lastword ${MAKEFILE_LIST}}}}
+# srcdir is the root of the source tree, computed as the directory part of the
+# last pathname in MAKEFILE_LIST – which is this file since there is no include
+# directive above this point.
+
+stage_bindir     = ${stagedir}${bindir}
+stage_libexecdir = ${stagedir}${libexecdir}
+stage_datadir    = ${stagedir}${datadir}
+stage_sysconfdir = ${stagedir}${sysconfdir}
+stage_statedir   = ${stagedir}${statedir}
+stage_cachedir   = ${stagedir}${cachedir}
+stage_logdir     = ${stagedir}${logdir}
+stage_includedir = ${stagedir}${includedir}
+stage_libdir     = ${stagedir}${libdir}
+stage_gprdir     = ${stagedir}${gprdir}
+stage_localedir  = ${stagedir}${localedir}
+stage_mandir     = ${stagedir}${mandir}
+stage_infodir    = ${stagedir}${infodir}
+stage_miscdocdir = ${stagedir}${miscdocdir}
+# These are the directories where different kinds of files to be installed are
+# written during the build.
+
+preprocess_file = "${GNATPREP}" ${firstword ${filter %.gp,$^}} $@ \
+                  ${options_preprocessing} ${Gnatprep_arguments} \
+                  ${if ${filter ${notdir $@},${notdir ${usage_GPRs}}}, \
+                       ${usage_directories}, \
+                       '-DSrcdir="${srcdir}"'}
+# preprocess_file is a command for use in recipes. It runs the first .gp file
+# among the rule's prerequisites through Gnatprep to produce the target. If the
+# target is a usage project, then the usage-relevant directory variables are
+# conveyed to it as Gnatprep symbols. Otherwise srcdir is conveyed.
+
+build_GPR = "${GNAT_BUILDER}" -P ${firstword ${filter %.gpr,$^}} \
+            -aP${srcdir} -aP${builddir} -p \
+            ${options_building} ${builder_arguments} ${GNATFLAGS}
+# build_GPR is a command for use in recipes. It performs a build controlled by
+# the first project file among the rule's prerequisites.
+
+
+#
+# Containing makefiles should assign or append to these variables as needed:
+#
 
 ifneq (${origin build_GPRs},file)
-   build_GPRs :=
+   build_GPRs =
 endif
 # build_GPRs shall name one or more project files for building the software.
 # These project files will be used when "make" or "make build" is invoked.
 
 ifneq (${origin usage_GPRs},file)
-   usage_GPRs :=
+   usage_GPRs =
 endif
 # If the build produces libraries, then usage_GPRs shall name the project files
 # that other projects should import to link to the libraries. These project
 # files will be installed to the target system.
 
+ifneq (${origin preprocessed_files},file)
+   preprocessed_files = \
+      ${filter-out ${notdir ${usage_GPRs}}, \
+                   ${basename ${notdir ${wildcard ${srcdir}/*.gp}}}}
+endif
+# preprocessed_files is a list of files to be produced in the preprocessing
+# step at the beginning of the build. Containing makefiles may override it or
+# append additional filenames to it.
+# The files are assumed to be needed during the build. The default list is all
+# the .gp files in srcdir except for usage projects, minus the .gp suffix. This
+# includes comfignat.gpr.
+
 ifneq (${origin options},file)
-   options :=
+   options =
 endif
 # options may be assigned a list of variable names. Those variables may be
 # overridden on the command line, and will be defined as Gnatprep symbols.
@@ -130,65 +212,255 @@ endif
 # The containing makefile should assign a default value to each variable unless
 # it shall be mandatory to always set the option on the command line.
 
-ifneq (${origin Gnatprep_definitions},file)
-   Gnatprep_definitions :=
+ifneq (${origin Gnatprep_arguments},file)
+   Gnatprep_arguments =
 endif
-# Any text assigned to Gnatprep_definitions will be included in the Gnatprep
+# Any text assigned to Gnatprep_arguments will be included in the Gnatprep
 # command line. It may be used for additional symbol definitions.
 
+ifneq (${origin builder_arguments},file)
+   builder_arguments =
+endif
+# Any text assigned to builder_arguments will be included in the GPRbuild or
+# Gnatmake command line. It may be used for external variables for project
+# files or other arguments that are essential for the build to work. Global
+# default values for optional arguments should be set in the options variables
+# instead.
+
+VPATH += ${srcdir} ${builddir}
+# VPATH is a list of directories that Make should search for prerequisites.
+
+configuration_variables += \
+   GNATPREP GNAT_BUILDER \
+   GNAT_BUILDER_FLAGS ADAFLAGS CPPFLAGS CFLAGS CXXFLAGS FFLAGS GNATBINDFLAGS \
+   GNATLINKFLAGS LDFLAGS GNATFLAGS \
+   DESTDIR \
+   dirgpr relocatable_package \
+   prefix exec_prefix datarootdir localstatedir \
+   bindir libexecdir datadir sysconfdir statedir cachedir logdir includedir \
+   libdir gprdir localedir mandir infodir miscdocdir runtimedir lockdir \
+   objdir stagedir \
+   install_cp_flags \
+   ${options}
+# configuration_variables is a list of variables that can be saved in the
+# persistent configuration with "make configure". Containing makefiles may
+# append additional variable names.
+
+
+#
+# Read the configuration file if there is one:
+#
+
+configuration = ${builddir}/comfignat_configuration.mk
+
+-include ${configuration}
+
 
 #
-# Compute the symbol definitions for Gnatprep, and some other data that the
-# rules need:
+# Ensure that builddir, objdir and stagedir are absolute pathnames:
 #
 
-# Convey objdir and stagedir to Gnatprep.
-definitions = '-DObjdir="${objdir}"' '-DStagedir="${stagedir}"'
+ifeq (${origin builddir},command line)
+   override builddir := ${abspath ${builddir}}
+endif
+ifeq (${origin objdir},command line)
+   override objdir := ${abspath ${objdir}}
+   objdir_is_configured = true
+endif
+ifeq (${origin stagedir},command line)
+   override stagedir := ${abspath ${stagedir}}
+   stagedir_is_configured = true
+endif
+# These pathnames need to be absolute in project files, because a pathname
+# relative to a project file can be wrong when a separate build directory is
+# used and project files are both in srcdir and in builddir. objdir and
+# stagedir also need to be absolute in the configuration file because the
+# working directory might change between Make invocations.
+# Once modified the variables are no longer of command line origin, so they are
+# marked as configured so that "make configure" will save them.
+
 
-# Convey the prefix variables too, although they're supposed to be unused when
-# the preprocessing is done with Make.
-definitions += '-DPrefix="${prefix}"' '-DExec_Prefix="${exec_prefix}"'
+#
+# Compute symbol definitions for Gnatprep and external variable assignments for
+# build projects:
+#
+
+nil =
+inert_space = _Comfignat_magic_protective_space_character_substitute_
+inert_percent = _Comfignat_magic_protective_percent_character_substitute_
+mung_string = ${subst %,${inert_percent},${subst ${nil} ,${inert_space},${1}}}
+unmung_string = ${subst ${inert_percent},%,${subst ${inert_space}, ,${1}}}
+# mung_string and unmung_string are used to prevent Make from interpreting
+# space and percent characters in strings.
+
+relativize = ${if ${filter ${2}%,${1}}, \
+                  ${3}${1:${2}%=%}, \
+                  ${call relativize,${1},${dir ${2:%/=%}},${3}../}}
+# relativize is the recursive algorithm that converts an absolute pathname into
+# a relative one.
+# Parameters:
+#    1: an absolute pathname to convert to relative
+#    2: the absolute base pathname, being shortened until it's a prefix of 1
+#    3: a growing series of "../" to lead the relative pathname with
+# If 2 is a prefix of 1, then return 3 concatenated with the part of 1 that
+# differs from 2. Otherwise delete the last element of 2, add one level of
+# "../" to 3, and repeat.
+# Within relativize all pathnames have one trailing slash so that only whole
+# directory names will match. Otherwise "/usr/lib" could match "/usr/lib64" for
+# example.
+
+prepare_pathname = ${subst //,/,${abspath ${call mung_string,${1}}}/}
+# prepare_pathname prepares a pathname for use as a parameter to relativize.
+#    · Protect space and percent characters from interpretation by Make.
+#    · Normalize the pathname, eliminating ".", ".." and "//".
+#    · Append a slash.
+#    · If the input was "/", then it is now "//". Change that back to "/".
+
+relative_to = \
+   ${or ${call unmung_string \
+              ,${patsubst %/,%,${call relativize \
+                                     ,${call prepare_pathname,${1}} \
+                                     ,${call prepare_pathname,${2}},}}},.}
+# relative_to converts an absolute pathname into a relative one. What it
+# actually does is to prepare the input to relativize and fix up its output.
+# Parameters:
+#    1: an absolute pathname to convert to relative
+#    2: the absolute base pathname that 1 shall be made relative to
+# Processing:
+#    · Prepare the two input pathnames with prepare_pathname.
+#    · Call relativize with the prepared pathnames for parameters 1 and 2, and
+#      an empty string for 3.
+#    · Strip the result of surrounding spaces and the trailing slash.
+#    · Reverse the protection of space and percent characters.
+#    · If the result is an empty string, then return "." instead.
+
+maybe_relative_to = \
+   ${if ${or ${filter-out 1,${words ${relocatable_package}}}, \
+             ${filter-out true false,${relocatable_package}}}, \
+        ${error relocatable_package must be "true" or "false"} \
+       ,${if ${filter true,${relocatable_package}} \
+            ,${call relative_to,${1},${2}},${1}}}
+# maybe_relative_to converts an absolute pathname into a relative one if a
+# relocatable package is desired.
+# Parameters:
+#    1: an absolute pathname to convert to relative
+#    2: the absolute base pathname that 1 may be made relative to
+# First check that the value of relocatable_package is a single word and that
+# that word is either "true" or "false". Complain and stop if that isn't so.
+# Then, if relocatable_package is "true", let relative_to convert the pathname,
+# otherwise return parameter 1 unchanged.
+
+embed_pathname = ${call maybe_relative_to,${1},${bindir}}
+# embed_pathname converts an absolute pathname into the right form for
+# inclusion in a program, which means that it is made relative to bindir if a
+# relocatable package is desired.
+
+usage_pathname = ${call maybe_relative_to,${1},${gprdir}}
+# usage_pathname converts an absolute pathname into the right form for
+# inclusion in a usage project, which means that it is made relative to gprdir
+# if a relocatable package is desired.
+
+# Convey builddir, objdir and stagedir to comfignat.gpr.
+all_directories = '-DBuilddir="${builddir}"' '-DObjdir="${objdir}"' \
+                  '-DStagedir="${stagedir}"'
+
+# Convey the builder-irrelevant directory variables, making them available to
+# build projects for inclusion in binaries. Make most of the pathnames relative
+# if a relocatable package is desired.
+all_directories += '-DDatadir="${call embed_pathname,${datadir}}"'
+all_directories += '-DSysconfdir="${call embed_pathname,${sysconfdir}}"'
+all_directories += '-DStatedir="${call embed_pathname,${statedir}}"'
+all_directories += '-DCachedir="${call embed_pathname,${cachedir}}"'
+all_directories += '-DLogdir="${call embed_pathname,${logdir}}"'
+all_directories += '-DGPRdir="${call embed_pathname,${gprdir}}"'
+all_directories += '-DLocaledir="${call embed_pathname,${localedir}}"'
+all_directories += '-DMandir="${call embed_pathname,${mandir}}"'
+all_directories += '-DInfodir="${call embed_pathname,${infodir}}"'
+all_directories += '-DMiscdocdir="${call embed_pathname,${miscdocdir}}"'
+all_directories += '-DRuntimedir="${runtimedir}"'
+all_directories += '-DLockdir="${lockdir}"'
+# runtimedir and lockdir belong to the operating system and are used for
+# communication between subsystems. It wouldn't make sense for an application
+# to have its own runtimedir. Therefore these variables are always absolute
+# pathnames.
 
-# If a directory project is used, then make project files take the directory
-# variables from there. Otherwise convey the ones defined above.
 ifeq (${dirgpr},)
-   definitions += '-DBindir="${bindir}"' '-DLibexecdir="${libexecdir}"'
-   definitions += '-DIncludedir="${includedir}"' '-DLibdir="${libdir}"'
+
+   # No directories project was provided, so convey even the builder-relevant
+   # directory variables to comfignat.gpr, and convey the usage-relevant ones
+   # to usage projects in the form that usage projects need.
+
+   all_directories += '-DBindir="${call embed_pathname,${bindir}}"'
+   all_directories += '-DLibexecdir="${call embed_pathname,${libexecdir}}"'
+   all_directories += '-DIncludedir="${call embed_pathname,${includedir}}"'
+   all_directories += '-DLibdir="${call embed_pathname,${libdir}}"'
+
+   all_directories += '-DStage_Bindir="${stage_bindir}"'
+   all_directories += '-DStage_Libexecdir="${stage_libexecdir}"'
+   all_directories += '-DStage_Includedir="${stage_includedir}"'
+   all_directories += '-DStage_Libdir="${stage_libdir}"'
+
+   usage_directories = '-DIncludedir="${call usage_pathname,${includedir}}"' \
+                       '-DLibdir="${call usage_pathname,${libdir}}"'
+
 else
-   directory_project := ${basename ${notdir ${dirgpr}}}
-   definitions += '-DDirectory_GPR="${dirgpr}"'
-   definitions += '-DDirectory_Project=${directory_project}'
-   definitions += '-DBindir=${directory_project}.Bindir'
-   definitions += '-DLibexecdir=${directory_project}.Libexecdir'
-   definitions += '-DIncludedir=${directory_project}.Includedir'
-   definitions += '-DLibdir=${directory_project}.Libdir'
+
+   # A directories project is used, so make project files take the builder-
+   # relevant directory variables from there.
+
+   directories_project := ${basename ${notdir ${call mung_string,${dirgpr}}}}
+
+   all_directories += '-DDirectories_GPR="${dirgpr}"'
+   all_directories += '-DDirectories_Project=${directories_project}'
+   all_directories += '-DBindir=${directories_project}.Bindir'
+   all_directories += '-DLibexecdir=${directories_project}.Libexecdir'
+   all_directories += '-DIncludedir=${directories_project}.Includedir'
+   all_directories += '-DLibdir=${directories_project}.Libdir'
+
+   usage_directories = '-DDirectories_GPR="${dirgpr}"' \
+                       '-DIncludedir=${directories_project}.Includedir' \
+                       '-DLibdir=${directories_project}.Libdir'
+
 endif
 
-# Convey boolean options to Gnatprep.
-definitions += \
-   ${foreach option,${options},\
-             ${if ${and ${filter-out environment,${origin ${option}}},\
-                        ${filter 1,${words ${${option}}}},\
-                        ${filter true false,${${option}}}},\
-                  -D${option}=${${option}},\
-                  ${error ${option} must be "true" or "false".}}}
+option_values = \
+   ${foreach option,${options}, \
+             ${if ${and ${filter-out environment,${origin ${option}}}, \
+                        ${filter 1,${words ${${option}}}}, \
+                        ${filter true false,${${option}}}}, \
+                  ${option}=${${option}}, \
+                  ${error ${option} must be "true" or "false"}}}
 # For each variable listed in options, check that it didn't come from the
 # environment (to prevent accidents), that its value is a single word, and that
-# that word is either "true" or "false". If so, append a symbol definition;
+# that word is either "true" or "false". If so, output a name/value pair;
 # otherwise complain and stop.
 
-# Convey any additional symbols that the containing makefile has defined.
-definitions += ${Gnatprep_definitions}
+# Convey boolean options to Gnatprep.
+options_preprocessing = ${addprefix -D,${option_values}}
 
-build_targets = ${addsuffix .phony_target,${build_GPRs}}
+# Convey boolean options to build projects.
+options_building = ${addprefix -X,${option_values}}
+
+
+#
+# Some other data that the rules below need:
+#
+
+delegation_command := @$${MAKE} --file=${abspath ${firstword ${MAKEFILE_LIST}}}\
+                     --include-dir=${srcdir} --no-print-directory
+# delegation_command is the Make command line that delegating makefiles in
+# separate build directories use to delegate commands to the main makefile. The
+# first pathname in MAKEFILE_LIST is the main makefile.
 
-stage_any_GPRs = ${if ${usage_GPRs},stage_GPRs}
+build_targets = ${addsuffix .phony_target,${build_GPRs}}
+# A phony target is defined for each build project, and the job of determining
+# whether the project needs rebuilding is delegated to the builder.
 
-build_GPR = "${GNAT_BUILDER}" -P ${firstword ${filter %.gpr,$^}} -p \
-            ${GNATFLAGS} -margs
-# build_GPR is a command for use in recipies. It performs a build controlled by
-# the first project file among the rule's prerequisites. Arguments for the
-# builder may be appended.
+staged_usage_GPRs = ${addprefix ${stage_gprdir}/,${usage_GPRs}}
+preprocessed_files_in_builddir = ${addprefix ${builddir}/,${preprocessed_files}}
+# When usage projects are preprocessed they are written to stage_gprdir. Other
+# preprocessed files are assumed to be needed during the build and are written
+# to builddir.
 
 
 #
@@ -197,24 +469,76 @@ build_GPR = "${GNAT_BUILDER}" -P ${firstword ${filter %.gpr,$^}} -p \
 
 .SECONDEXPANSION:
 
-all: build
-
-%.gpr: %.gpr.in
-	"${GNATPREP}" $< $@ ${definitions}
-
-configure: $${configured_files}
-
-%.gpr.phony_target: %.gpr configure
+Comfignat_default_goal: build
+
+# How to make directories:
+${builddir} ${stage_gprdir}:
+	mkdir -p $@
+
+# How to initialize a build directory with a delegating makefile:
+${builddir}/Makefile: | ${builddir}
+	@echo 'Writing $@.'
+	@( echo 'Comfignat_default_goal: force ; ${delegation_command}'; \
+	   echo '%: force ; ${delegation_command} $$@'; \
+	   echo 'force: ;'; \
+	   echo 'Makefile: ;' \
+	 ) > $@
+# This rule generates a delegating makefile in a separate build directory. The
+# generated makefile delegates all commands to the main makefile. The default
+# rule invokes the main makefile without a specified goal, triggering the main
+# makefile's default goal. A match-anything rule forwards any specified goals
+# to the main makefile. An empty recipe for "Makefile" prevents Make from using
+# the match-anything rule to update the makefile.
+
+# How to save configured variables:
+configure:: ${builddir}/Makefile
+	@echo "Writing ${configuration}."
+	@( ${foreach variable,${configuration_variables}, \
+	             ${if ${or ${findstring command line, \
+	                                    ${origin ${variable}}}, \
+	                       ${filter true,${${variable}_is_configured}}}, \
+	                  echo 'ifneq "$${origin ${variable}}" "command line"';\
+	                  echo 'override ${variable} = ${value ${variable}}'; \
+	                  echo 'endif'; \
+	                  echo '${variable}_is_configured = true';}} \
+	   true \
+	 ) > "${configuration}"
+# Out of the variables listed in configuration_variables, all that were
+# overridden on the command line, and all that were previously configured, are
+# written to the configuration file. Configured values override defaults
+# defined later in the containing makefile, but can be overridden on the
+# command line. A variable is considered previously configured if there is
+# another variable with "_is_configured" appended to its name and a value of
+# "true". Such a variable is also written for each configured variable. As a
+# side effect of this it is possible to delete a variable V from the
+# configuration by running "make configure V_is_configured=false".
+
+# How to preprocess the project Comfignat:
+${builddir}/comfignat.gpr: comfignat.gpr.gp | ${builddir}
+	"${GNATPREP}" $< $@ -DInvoked_By_Makefile ${all_directories}
+
+# How to preprocess files that are needed during the build:
+${builddir}/%: %.gp | ${builddir}
+	${preprocess_file}
+
+# How to preprocess usage projects:
+${stage_gprdir}/%: %.gp | ${stage_gprdir}
+	${preprocess_file}
+
+# How to stage usage projects that don't need preprocessing:
+${stage_gprdir}/%: % | ${stage_gprdir}
+	cp -p $< $@
+
+preprocess: $${preprocessed_files_in_builddir}
+
+# How to build a project:
+%.gpr.phony_target: %.gpr preprocess
 	${build_GPR}
 # Instead of tracking dependencies between project files, this rule simply
-# requires that all preprocessing is done before any project is built.
+# requires that all preprocessing of files that are needed during the build is
+# done before any project is built.
 
-stage_GPRs: $${usage_GPRs}
-	mkdir -p "${stagedir}${gprdir}"
-	cp -p ${usage_GPRs} "${stagedir}${gprdir}"
-.PHONY: stage_GPRs
-
-build: $${build_targets} $${stage_any_GPRs}
+build: $${build_targets} $${staged_usage_GPRs}
 
 ${stagedir}:
 	@${MAKE} build --no-print-directory
@@ -222,10 +546,16 @@ ${stagedir}:
 # something has been built then "make install" doesn't rebuild anything, just
 # copies the built files to their destination.
 
+# How to install what has been built and staged:
 install: ${stagedir}
 	mkdir -p "${DESTDIR}/"
 	cp -RPf ${install_cp_flags} "${stagedir}"/* "${DESTDIR}/"
 .PHONY: install
 
 clean::
-	rm -Rf ${builddir} ${configured_files}
+	rm -Rf "${objdir}" "${stagedir}" ${preprocessed_files_in_builddir}
+
+unconfigure::
+	rm -f "${configuration}"
+
+distclean: clean unconfigure
diff --git a/system_log.gpr.in b/system_log.gpr.gp
index bfd2521..c9f6f76 100644
--- a/system_log.gpr.in
+++ b/system_log.gpr.gp
@@ -6,8 +6,8 @@
 -- by the Free Software Foundation.
 
 
-#if Directory_GPR'Defined then
-with $Directory_GPR;
+#if Directories_GPR'Defined then
+with $Directories_GPR;
 #end if;
 
 library project System_Log is