Issue #4201: meson: pdbgen not working.

Fix the dependency by making the stamp an actual (yet empty/no-op)
header file which is included by all generated source file. This way, we
ensure that meson rebuild .o files when the .pdb sources are changed.

This is the second solution proposed by eli-schwartz here:
https://github.com/mesonbuild/meson/issues/10196#issuecomment-1080053413

app/pdb/Makefile.am

@@ -5,6 +5,7 @@ AM_CPPFLAGS = \
 	-I$(top_builddir)		\
 	-I$(top_srcdir)			\
 	-I$(top_builddir)/app		\
+	-I$(top_builddir)/pdb		\
 	-I$(top_srcdir)/app		\
 	$(CAIRO_CFLAGS)			\
 	$(GEGL_CFLAGS)			\

app/pdb/brush-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <string.h>
 
 #include <gegl.h>

app/pdb/brush-select-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/brushes-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <string.h>
 
 #include <gegl.h>

app/pdb/buffer-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <string.h>
 
 #include <gegl.h>

app/pdb/channel-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <cairo.h>
 
 #include <gegl.h>

app/pdb/context-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <cairo.h>
 
 #include <gegl.h>

app/pdb/debug-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/display-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/drawable-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/drawable-color-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/drawable-edit-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/dynamics-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/edit-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/file-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <string.h>
 
 #include <gegl.h>

app/pdb/floating-sel-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/font-select-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/fonts-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/gimp-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/gimprc-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <string.h>
 
 #include <gegl.h>

app/pdb/gradient-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <cairo.h>
 #include <string.h>
 

app/pdb/gradient-select-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/gradients-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <string.h>
 
 #include <gegl.h>

app/pdb/help-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/image-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <cairo.h>
 
 #include <gegl.h>

app/pdb/image-color-profile-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <cairo.h>
 
 #include <gegl.h>

app/pdb/image-convert-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/image-grid-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <cairo.h>
 
 #include <gegl.h>

app/pdb/image-guides-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/image-sample-points-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/image-select-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <cairo.h>
 
 #include <gegl.h>

app/pdb/image-transform-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/image-undo-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/internal-procs.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <glib-object.h>
 
 #include "pdb-types.h"

app/pdb/item-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/item-transform-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/layer-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <cairo.h>
 
 #include <gegl.h>

app/pdb/message-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <string.h>
 
 #include <gegl.h>

app/pdb/paint-tools-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/palette-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <cairo.h>
 #include <string.h>
 

app/pdb/palette-select-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/palettes-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <string.h>
 
 #include <gegl.h>

app/pdb/pattern-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <string.h>
 
 #include <gegl.h>

app/pdb/pattern-select-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/patterns-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <string.h>
 
 #include <gegl.h>

app/pdb/pdb-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/plug-in-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <stdlib.h>
 #include <string.h>
 

app/pdb/plug-in-compat-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <cairo.h>
 
 #include <gegl.h>

app/pdb/progress-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/selection-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/text-layer-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <cairo.h>
 
 #include <gegl.h>

app/pdb/text-tool-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/unit-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <gegl.h>
 
 #include <gdk-pixbuf/gdk-pixbuf.h>

app/pdb/vectors-cmds.c

@@ -19,6 +19,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include <string.h>
 
 #include <gegl.h>

libgimp/Makefile.am

@@ -74,6 +74,7 @@ AM_CPPFLAGS = \
 	-DG_LOG_DOMAIN=\"LibGimp\"	\
 	-DGIMP_COMPILATION		\
 	-I$(top_srcdir)			\
+	-I$(top_builddir)/pdb		\
 	$(GTK_CFLAGS)			\
 	$(GEGL_CFLAGS)			\
 	$(GEXIV2_CFLAGS)		\

libgimp/gimp_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpbrush_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpbrushes_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpbrushselect_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpbuffer_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpchannel_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpcontext_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpdebug_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpdisplay_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpdrawable_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpdrawablecolor_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpdrawableedit_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpdynamics_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpedit_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpfile_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpfloatingsel_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpfonts_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpfontselect_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpgimprc_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpgradient_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpgradients_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpgradientselect_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimphelp_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpimage_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpimagecolorprofile_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpimageconvert_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpimagegrid_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpimageguides_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpimagesamplepoints_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpimageselect_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpimagetransform_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpimageundo_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpitem_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpitemtransform_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimplayer_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimpmessage_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimppainttools_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimppalette_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimppalettes_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimppaletteselect_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimppattern_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimppatterns_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimppatternselect_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 
 

libgimp/gimppdb_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 #include "gimppdb_pdb.h"
 

libgimp/gimpplugin_pdb.c

@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include "stamp-pdbgen.h"
+
 #include "gimp.h"
 #include "gimpplugin_pdb.h"