Description: allow caller to override build flags
 configure.in: accept ADAFLAGS like CFLAGS and friends, and transmit
 all of them to generated files. This part has been refused upstream,
 because it may be replaced with appropriate GPRBUILD_OPTIONS
 and would encourage users to use untested combinations.
 .
 Makefile.in: allow user to override default gprbuild options.
 .
 Builder options in shared.gpr.in (-jPROCESSORS -m -p) override the
 same settings in Makefile.in. For example, "make PROCESSORS=2" is
 silently ignored. One of them has to disappear.
 .
 shared.gpr.in *.gpr: *FLAGS given to configure should be able to
 override default *switches in projects. Refused upstream, see above.
 .
 Set Library_Options in opengl.gpr, as in upstream commit
 https://github.com/AdaCore/gtkada/commit/77ce088e84b9d1a2de2ed78c5d7d30596ba33579#diff-ab95eddae77bed1dc4a1ef6544cbdaef.
 .
 aclocal.m4: LDFLAGS should be extended, neither erased nor inserted
 into GTK_LIBS. LIBS should be appended to GTK_LIBS instead of
 prepended (to be compatible with --Wl,--as-needed).
Author: Nicolas Boulenguez <nicolas@debian.org>
Forwarded: https://github.com/AdaCore/gtkada/commit/901a766ce2b4bf4fcda25178a8c95774762da9ad

--- a/configure.in
+++ b/configure.in
@@ -7,6 +7,13 @@
 fi
 AC_SUBST(TARGET)
 
+AC_ARG_VAR(ADAFLAGS,Debugging and optimization options for the Ada compiler)
+AM_TO_GPR( $ADAFLAGS,  ADAFLAGS_GPR)
+AM_TO_GPR(   $CFLAGS,    CFLAGS_GPR)
+AM_TO_GPR( $CPPFLAGS,  CPPFLAGS_GPR)
+AM_TO_GPR(  $LDFLAGS,   LDFLAGS_GPR)
+AM_TO_GPR($OBJCFLAGS, OBJCFLAGS_GPR)
+
 AM_ADD_OS_SPECIFIC_FLAGS
 
 # checking for local tools
--- a/Makefile.in
+++ b/Makefile.in
@@ -32,7 +32,8 @@
 # Number of parallel compilation
 PROCESSORS   = 0
 
-GPRBUILD_FULL = ${GPRBUILD} -j${PROCESSORS} -m -p
+GPRBUILD_OPTIONS =
+GPRBUILD_FULL = ${GPRBUILD} -j${PROCESSORS} -m -p ${GPRBUILD_OPTIONS}
 
 GETTEXT_INTL=@GETTEXT_INTL@
 HAVE_GETTEXT=@HAVE_GETTEXT@
--- a/shared.gpr.in
+++ b/shared.gpr.in
@@ -3,9 +3,6 @@
    type Build_Type is ("Debug", "Production");
    Build : Build_Type := external ("BUILD", "@BUILD_TYPE@");
 
-   Processors := external ("PROCESSORS", "0");
-   --  Number of parallel compilations that should be performed
-
    type Boolean_Type is ("True", "False");
    Build_Opengl : Boolean_Type := "@HAVE_OPENGL@";
 
@@ -19,6 +16,11 @@
 
    So_Ext := "@SO_EXT@";
    Version := "@PACKAGE_VERSION@";
+   Adaflags    := (@ADAFLAGS_GPR@);
+   Cflags      := (@CFLAGS_GPR@);
+   Cppflags    := (@CPPFLAGS_GPR@);
+   Ldflags     := (@LDFLAGS_GPR@);
+   Objcflags   := (@OBJCFLAGS_GPR@);
    Gtk_Include := (@GTK_CFLAGS_GPR@);
    Gtk_Libs    := (@GTK_LIBS_GPR@);
    GL_Include  := (@GL_CFLAGS_GPR@);
@@ -45,14 +47,16 @@
                  "-Werror=format-security");
              for Switches ("C") use ("-O2");
       end case;
+      for Switches ("Ada") use Compiler'Switches ("Ada") & Adaflags;
+      for Switches ("C") use Compiler'Switches ("C") & Cppflags & Cflags;
+      for Switches ("Objective-C") use Compiler'Switches ("Objective-C")
+        & Objcflags;
 
       for Switches ("C") use Compiler'Switches ("C") & Gtk_Include;
       for Switches ("Objective-C") use Compiler'Switches ("Objective-C") & Gtk_Include;
    end Compiler;
 
    package Builder is
-      for Switches ("Ada") use ("-m", "-j" & Processors);
-
       case Build is
          when "Debug" =>
             for Global_Configuration_Pragmas use Shared'Project_Dir & "src/gnat_debug.adc";
@@ -70,6 +74,10 @@
       end case;
    end Binder;
 
+   package Linker is
+      for Leading_Switches ("Ada") use Ldflags;
+   end Linker;
+
    package IDE is
       for VCS_Kind use "auto";
       for Documentation_Dir use "html";
--- a/src/gtkada_src.gpr
+++ b/src/gtkada_src.gpr
@@ -16,6 +16,7 @@
    for Library_Name use "gtkada";
    for Library_Version use
       "lib" & Project'Library_Name & Shared.So_Ext & "." & Shared.Version;
+   for Leading_Library_Options use Shared.Ldflags;
    for Library_Options use Shared.Gtk_Libs;
 
    package Builder  renames Shared.Builder;
--- a/src/opengl/opengl.gpr
+++ b/src/opengl/opengl.gpr
@@ -16,6 +16,8 @@
    for Library_Dir use "../lib/" & Project'Library_Name & "/" & Project'Library_Kind;
    for Library_Version use
       "lib" & Project'Library_Name & Shared.So_Ext & "." & Shared.Version;
+   for Leading_Library_Options use Shared.Ldflags;
+   for Library_Options use Shared.GL_Libs;
 
    package Builder  renames Shared.Builder;
    package Compiler is
@@ -30,4 +32,3 @@
       for Linker_Options use Shared.GL_Libs;
    end Linker;
 end OpenGL;
-
--- a/src/tools/tools.gpr
+++ b/src/tools/tools.gpr
@@ -12,5 +12,6 @@
 
    package Compiler renames Shared.Compiler;
    package Binder   renames Shared.Binder;
+   package Linker   renames Shared.Linker;
    package IDE      renames Shared.IDE;
 end Tools;
--- a/testgtk/testgtk.gpr
+++ b/testgtk/testgtk.gpr
@@ -30,6 +30,7 @@
       for Switches ("C") use Shared.Compiler'Switches ("C");
    end Compiler;
    package Binder   renames Shared.Binder;
+   package Linker   renames Shared.Linker;
    package IDE      renames Shared.IDE;
 
 end TestGtk;
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -88,7 +88,7 @@
          BUILD_SHARED=yes
       fi
       SO_OPTS="-Wl,-undefined,dynamic_lookup -dynamiclib -Wl,-dylib_install_name,"
-      LDFLAGS="-Wl,-framework,Cocoa"
+      LDFLAGS="$LDFLAGS -Wl,-framework,Cocoa"
       TARGET_LFLAGS="-Wl,-framework,Cocoa"
       ;;
    # ??? The following case has been introduced because of an elaboration
@@ -274,15 +274,11 @@
     if test $? != 0 ; then
        AC_MSG_ERROR([old version detected])
     fi
-    
+
     GTK_PREFIX=`$PKG_CONFIG $GTK --variable=prefix`
     GTK_CFLAGS=`$PKG_CONFIG $GTK --cflags`
     GTK_LIBS=`$PKG_CONFIG $GTK gmodule-2.0 --libs`
 
-    dnl force some explicit flags, like -framework Cocoa. On some machines,
-    dnl these are added automatically by pkg-config, but not systematically.
-    GTK_LIBS="$GTK_LIBS $LDFLAGS"
-
     dnl
     dnl Now check if the installed GTK is sufficiently new. (Also sanity
     dnl checks the results of pkg-config to some extent
@@ -325,6 +321,8 @@
      *mingw*) GTK_LIBS="-L../../lib -L../../bin $GTK_LIBS";;
   esac
 
+  GTK_LIBS="$GTK_LIBS $LIBS"
+
   AM_TO_GPR($GTK_LIBS, GTK_LIBS_GPR)
   rm -f conf.gtktest
 ])