diff --git a/app/config/Makefile.am b/app/config/Makefile.am
index 9686e357c1..faaa21e1a0 100644
--- a/app/config/Makefile.am
+++ b/app/config/Makefile.am
@@ -144,7 +144,7 @@ CLEANFILES += $(gen_sources)
 
 xgen-cec: $(srcdir)/config-enums.h $(GIMP_MKENUMS) Makefile.am
 	$(AM_V_GEN) $(GIMP_MKENUMS) \
-		--fhead "#include \"config.h\"\n#include <gio/gio.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"config-enums.h\"\n#include \"gimp-intl.h\"" \
+		--fhead "#include \"stamp-config-enums.h\"\n#include \"config.h\"\n#include <gio/gio.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"config-enums.h\"\n#include \"gimp-intl.h\"" \
 		--fprod "\n/* enumerations from \"@basename@\" */" \
 		--vhead "GType\n@enum_name@_get_type (void)\n{\n  static const G@Type@Value values[] =\n  {" \
 		--vprod "    { @VALUENAME@, \"@VALUENAME@\", \"@valuenick@\" }," \
@@ -154,11 +154,14 @@ xgen-cec: $(srcdir)/config-enums.h $(GIMP_MKENUMS) Makefile.am
 		--dtail "    { 0, NULL, NULL }\n  };\n\n  static GType type = 0;\n\n  if (G_UNLIKELY (! type))\n    {\n      type = g_@type@_register_static (\"@EnumName@\", values);\n      gimp_type_set_translation_context (type, \"@enumnick@\");\n      gimp_@type@_set_value_descriptions (type, descs);\n    }\n\n  return type;\n}\n" \
 		$< > $@
 
+stamp-config-enums.h: xgen-cec
+	echo "/* Generated on `date`. */" > $@
+
 # copy the generated enum file back to the source directory only if it's
 # changed; otherwise, only update its timestamp, so that the recipe isn't
 # executed again on the next build, however, allow this to (harmlessly) fail,
 # to support building from a read-only source tree.
-$(srcdir)/config-enums.c: xgen-cec
+$(srcdir)/config-enums.c: xgen-cec stamp-config-enums.h
 	$(AM_V_GEN) if ! cmp -s $< $@; then \
 		cp $< $@; \
 	else \
diff --git a/app/core/Makefile.am b/app/core/Makefile.am
index c9439abc4c..61d5d0ba67 100644
--- a/app/core/Makefile.am
+++ b/app/core/Makefile.am
@@ -545,7 +545,7 @@ gimpmarshal.c: gimpmarshal.h
 
 xgen-cec: $(srcdir)/core-enums.h $(GIMP_MKENUMS) Makefile.am
 	$(AM_V_GEN) $(GIMP_MKENUMS) \
-		--fhead "#include \"config.h\"\n#include <gio/gio.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"core-enums.h\"\n#include \"gimp-intl.h\"" \
+		--fhead "#include \"stamp-core-enums.h\"\n#include \"config.h\"\n#include <gio/gio.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"core-enums.h\"\n#include \"gimp-intl.h\"" \
 		--fprod "\n/* enumerations from \"@basename@\" */" \
 		--vhead "GType\n@enum_name@_get_type (void)\n{\n  static const G@Type@Value values[] =\n  {" \
 		--vprod "    { @VALUENAME@, \"@VALUENAME@\", \"@valuenick@\" }," \
@@ -555,11 +555,14 @@ xgen-cec: $(srcdir)/core-enums.h $(GIMP_MKENUMS) Makefile.am
 		--dtail "    { 0, NULL, NULL }\n  };\n\n  static GType type = 0;\n\n  if (G_UNLIKELY (! type))\n    {\n      type = g_@type@_register_static (\"@EnumName@\", values);\n      gimp_type_set_translation_context (type, \"@enumnick@\");\n      gimp_@type@_set_value_descriptions (type, descs);\n    }\n\n  return type;\n}\n" \
 		$< > $@
 
+stamp-core-enums.h: xgen-cec
+	echo "/* Generated on `date`. */" > $@
+
 # copy the generated enum file back to the source directory only if it's
 # changed; otherwise, only update its timestamp, so that the recipe isn't
 # executed again on the next build, however, allow this to (harmlessly) fail,
 # to support building from a read-only source tree.
-$(srcdir)/core-enums.c: xgen-cec
+$(srcdir)/core-enums.c: xgen-cec stamp-core-enums.h
 	$(AM_V_GEN) if ! cmp -s $< $@; then \
 		cp $< $@; \
 	else \
diff --git a/app/display/Makefile.am b/app/display/Makefile.am
index 2bc9b510c0..fbea77b482 100644
--- a/app/display/Makefile.am
+++ b/app/display/Makefile.am
@@ -205,7 +205,7 @@ CLEANFILES = $(gen_sources)
 
 xgen-dec: $(srcdir)/display-enums.h $(GIMP_MKENUMS) Makefile.am
 	$(AM_V_GEN) $(GIMP_MKENUMS) \
-		--fhead "#include \"config.h\"\n#include <gio/gio.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"display-enums.h\"\n#include \"gimp-intl.h\"" \
+		--fhead "#include \"stamp-display-enums.h\"\n#include \"config.h\"\n#include <gio/gio.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"display-enums.h\"\n#include \"gimp-intl.h\"" \
 		--fprod "\n/* enumerations from \"@basename@\" */" \
 		--vhead "GType\n@enum_name@_get_type (void)\n{\n  static const G@Type@Value values[] =\n  {" \
 		--vprod "    { @VALUENAME@, \"@VALUENAME@\", \"@valuenick@\" }," \
@@ -215,11 +215,14 @@ xgen-dec: $(srcdir)/display-enums.h $(GIMP_MKENUMS) Makefile.am
 		--dtail "    { 0, NULL, NULL }\n  };\n\n  static GType type = 0;\n\n  if (G_UNLIKELY (! type))\n    {\n      type = g_@type@_register_static (\"@EnumName@\", values);\n      gimp_type_set_translation_context (type, \"@enumnick@\");\n      gimp_@type@_set_value_descriptions (type, descs);\n    }\n\n  return type;\n}\n" \
 		$< > $@
 
+stamp-display-enums.h: xgen-dec
+	echo "/* Generated on `date`. */" > $@
+
 # copy the generated enum file back to the source directory only if it's
 # changed; otherwise, only update its timestamp, so that the recipe isn't
 # executed again on the next build, however, allow this to (harmlessly) fail,
 # to support building from a read-only source tree.
-$(srcdir)/display-enums.c: xgen-dec
+$(srcdir)/display-enums.c: xgen-dec stamp-display-enums.h
 	$(AM_V_GEN) if ! cmp -s $< $@; then \
 		cp $< $@; \
 	else \
diff --git a/app/gegl/Makefile.am b/app/gegl/Makefile.am
index e4020563c1..8f9d2adec7 100644
--- a/app/gegl/Makefile.am
+++ b/app/gegl/Makefile.am
@@ -76,7 +76,7 @@ CLEANFILES = $(gen_sources)
 
 xgen-ggec: $(srcdir)/gimp-gegl-enums.h $(GIMP_MKENUMS) Makefile.am
 	$(AM_V_GEN) $(GIMP_MKENUMS) \
-		--fhead "#include \"config.h\"\n#include <gio/gio.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"core/core-enums.h\"\n#include \"gimp-gegl-enums.h\"\n#include \"gimp-intl.h\"" \
+		--fhead "#include \"stamp-gimp-gegl-enums.h\"\n#include \"config.h\"\n#include <gio/gio.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"core/core-enums.h\"\n#include \"gimp-gegl-enums.h\"\n#include \"gimp-intl.h\"" \
 		--fprod "\n/* enumerations from \"@basename@\" */" \
 		--vhead "GType\n@enum_name@_get_type (void)\n{\n  static const G@Type@Value values[] =\n  {" \
 		--vprod "    { @VALUENAME@, \"@VALUENAME@\", \"@valuenick@\" }," \
@@ -86,11 +86,14 @@ xgen-ggec: $(srcdir)/gimp-gegl-enums.h $(GIMP_MKENUMS) Makefile.am
 		--dtail "    { 0, NULL, NULL }\n  };\n\n  static GType type = 0;\n\n  if (G_UNLIKELY (! type))\n    {\n      type = g_@type@_register_static (\"@EnumName@\", values);\n      gimp_type_set_translation_context (type, \"@enumnick@\");\n      gimp_@type@_set_value_descriptions (type, descs);\n    }\n\n  return type;\n}\n" \
 		$< > $@
 
+stamp-gimp-gegl-enums.h: xgen-ggec
+	echo "/* Generated on `date`. */" > $@
+
 # copy the generated enum file back to the source directory only if it's
 # changed; otherwise, only update its timestamp, so that the recipe isn't
 # executed again on the next build, however, allow this to (harmlessly) fail,
 # to support building from a read-only source tree.
-$(srcdir)/gimp-gegl-enums.c: xgen-ggec
+$(srcdir)/gimp-gegl-enums.c: xgen-ggec stamp-gimp-gegl-enums.h
 	$(AM_V_GEN) if ! cmp -s $< $@; then \
 		cp $< $@; \
 	else \
diff --git a/app/operations/Makefile.am b/app/operations/Makefile.am
index 24bfe6d9eb..5b2facc29b 100644
--- a/app/operations/Makefile.am
+++ b/app/operations/Makefile.am
@@ -117,7 +117,7 @@ CLEANFILES = $(gen_sources)
 
 xgen-oec: $(srcdir)/operations-enums.h $(GIMP_MKENUMS) Makefile.am
 	$(AM_V_GEN) $(GIMP_MKENUMS) \
-		--fhead "#include \"config.h\"\n#include <gio/gio.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"operations-enums.h\"\n#include \"gimp-intl.h\"" \
+		--fhead "#include \"stamp-operations-enums.h\"\n#include \"config.h\"\n#include <gio/gio.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"operations-enums.h\"\n#include \"gimp-intl.h\"" \
 		--fprod "\n/* enumerations from \"@basename@\" */" \
 		--vhead "GType\n@enum_name@_get_type (void)\n{\n  static const G@Type@Value values[] =\n  {" \
 		--vprod "    { @VALUENAME@, \"@VALUENAME@\", \"@valuenick@\" }," \
@@ -127,11 +127,14 @@ xgen-oec: $(srcdir)/operations-enums.h $(GIMP_MKENUMS) Makefile.am
 		--dtail "    { 0, NULL, NULL }\n  };\n\n  static GType type = 0;\n\n  if (G_UNLIKELY (! type))\n    {\n      type = g_@type@_register_static (\"@EnumName@\", values);\n      gimp_type_set_translation_context (type, \"@enumnick@\");\n      gimp_@type@_set_value_descriptions (type, descs);\n    }\n\n  return type;\n}\n" \
 		$< > $@
 
+stamp-operations-enums.h: xgen-oec
+	echo "/* Generated on `date`. */" > $@
+
 # copy the generated enum file back to the source directory only if it's
 # changed; otherwise, only update its timestamp, so that the recipe isn't
 # executed again on the next build, however, allow this to (harmlessly) fail,
 # to support building from a read-only source tree.
-$(srcdir)/operations-enums.c: xgen-oec
+$(srcdir)/operations-enums.c: xgen-oec stamp-operations-enums.h
 	$(AM_V_GEN) if ! cmp -s $< $@; then \
 		cp $< $@; \
 	else \
diff --git a/app/paint/Makefile.am b/app/paint/Makefile.am
index 1cc625e896..b9248121d1 100644
--- a/app/paint/Makefile.am
+++ b/app/paint/Makefile.am
@@ -102,7 +102,7 @@ CLEANFILES = $(gen_sources)
 
 xgen-pec: $(srcdir)/paint-enums.h $(GIMP_MKENUMS) Makefile.am
 	$(AM_V_GEN) $(GIMP_MKENUMS) \
-		--fhead "#include \"config.h\"\n#include <gio/gio.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"paint-enums.h\"\n#include \"gimp-intl.h\"" \
+		--fhead "#include \"stamp-paint-enums.h\"\n#include \"config.h\"\n#include <gio/gio.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"paint-enums.h\"\n#include \"gimp-intl.h\"" \
 		--fprod "\n/* enumerations from \"@basename@\" */" \
 		--vhead "GType\n@enum_name@_get_type (void)\n{\n  static const G@Type@Value values[] =\n  {" \
 		--vprod "    { @VALUENAME@, \"@VALUENAME@\", \"@valuenick@\" }," \
@@ -112,11 +112,14 @@ xgen-pec: $(srcdir)/paint-enums.h $(GIMP_MKENUMS) Makefile.am
 		--dtail "    { 0, NULL, NULL }\n  };\n\n  static GType type = 0;\n\n  if (G_UNLIKELY (! type))\n    {\n      type = g_@type@_register_static (\"@EnumName@\", values);\n      gimp_type_set_translation_context (type, \"@enumnick@\");\n      gimp_@type@_set_value_descriptions (type, descs);\n    }\n\n  return type;\n}\n" \
 		$< > $@
 
+stamp-paint-enums.h: xgen-pec
+	echo "/* Generated on `date`. */" > $@
+
 # copy the generated enum file back to the source directory only if it's
 # changed; otherwise, only update its timestamp, so that the recipe isn't
 # executed again on the next build, however, allow this to (harmlessly) fail,
 # to support building from a read-only source tree.
-$(srcdir)/paint-enums.c: xgen-pec
+$(srcdir)/paint-enums.c: xgen-pec stamp-paint-enums.h
 	$(AM_V_GEN) if ! cmp -s $< $@; then \
 		cp $< $@; \
 	else \
diff --git a/app/plug-in/Makefile.am b/app/plug-in/Makefile.am
index f6b4f43014..b1944f0cf2 100644
--- a/app/plug-in/Makefile.am
+++ b/app/plug-in/Makefile.am
@@ -80,7 +80,7 @@ CLEANFILES = $(EXTRA_PROGRAMS) $(gen_sources)
 
 xgen-pec: $(srcdir)/plug-in-enums.h $(GIMP_MKENUMS) Makefile.am
 	$(AM_V_GEN) $(GIMP_MKENUMS) \
-		--fhead "#include \"config.h\"\n#include <gio/gio.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"plug-in-enums.h\"\n#include \"gimp-intl.h\"" \
+		--fhead "#include \"stamp-plug-in-enums.h\"\n#include \"config.h\"\n#include <gio/gio.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"plug-in-enums.h\"\n#include \"gimp-intl.h\"" \
 		--fprod "\n/* enumerations from \"@basename@\" */" \
 		--vhead "GType\n@enum_name@_get_type (void)\n{\n  static const G@Type@Value values[] =\n  {" \
 		--vprod "    { @VALUENAME@, \"@VALUENAME@\", \"@valuenick@\" }," \
@@ -90,11 +90,14 @@ xgen-pec: $(srcdir)/plug-in-enums.h $(GIMP_MKENUMS) Makefile.am
 		--dtail "    { 0, NULL, NULL }\n  };\n\n  static GType type = 0;\n\n  if (G_UNLIKELY (! type))\n    {\n      type = g_@type@_register_static (\"@EnumName@\", values);\n      gimp_type_set_translation_context (type, \"@enumnick@\");\n      gimp_@type@_set_value_descriptions (type, descs);\n    }\n\n  return type;\n}\n" \
 		$< > $@
 
+stamp-plug-in-enums.h: xgen-pec
+	echo "/* Generated on `date`. */" > $@
+
 # copy the generated enum file back to the source directory only if it's
 # changed; otherwise, only update its timestamp, so that the recipe isn't
 # executed again on the next build, however, allow this to (harmlessly) fail,
 # to support building from a read-only source tree.
-$(srcdir)/plug-in-enums.c: xgen-pec
+$(srcdir)/plug-in-enums.c: xgen-pec stamp-plug-in-enums.h
 	$(AM_V_GEN) if ! cmp -s $< $@; then \
 		cp $< $@; \
 	else \
diff --git a/app/text/Makefile.am b/app/text/Makefile.am
index de7616e07d..416b58e3f5 100644
--- a/app/text/Makefile.am
+++ b/app/text/Makefile.am
@@ -57,7 +57,7 @@ CLEANFILES = $(gen_sources)
 
 xgen-tec: $(srcdir)/text-enums.h $(GIMP_MKENUMS) Makefile.am
 	$(AM_V_GEN) $(GIMP_MKENUMS) \
-		--fhead "#include \"config.h\"\n#include <gio/gio.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"text-enums.h\"\n#include \"gimp-intl.h\"" \
+		--fhead "#include \"stamp-text-enums.h\"\n#include \"config.h\"\n#include <gio/gio.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"text-enums.h\"\n#include \"gimp-intl.h\"" \
 		--fprod "\n/* enumerations from \"@basename@\" */" \
 		--vhead "GType\n@enum_name@_get_type (void)\n{\n  static const G@Type@Value values[] =\n  {" \
 		--vprod "    { @VALUENAME@, \"@VALUENAME@\", \"@valuenick@\" }," \
@@ -67,11 +67,14 @@ xgen-tec: $(srcdir)/text-enums.h $(GIMP_MKENUMS) Makefile.am
 		--dtail "    { 0, NULL, NULL }\n  };\n\n  static GType type = 0;\n\n  if (G_UNLIKELY (! type))\n    {\n      type = g_@type@_register_static (\"@EnumName@\", values);\n      gimp_type_set_translation_context (type, \"@enumnick@\");\n      gimp_@type@_set_value_descriptions (type, descs);\n    }\n\n  return type;\n}\n" \
 		$< > $@
 
+stamp-text-enums.h: xgen-tec
+	echo "/* Generated on `date`. */" > $@
+
 # copy the generated enum file back to the source directory only if it's
 # changed; otherwise, only update its timestamp, so that the recipe isn't
 # executed again on the next build, however, allow this to (harmlessly) fail,
 # to support building from a read-only source tree.
-$(srcdir)/text-enums.c: xgen-tec
+$(srcdir)/text-enums.c: xgen-tec stamp-text-enums.h
 	$(AM_V_GEN) if ! cmp -s $< $@; then \
 		cp $< $@; \
 	else \
diff --git a/app/tools/Makefile.am b/app/tools/Makefile.am
index a9e7221c9e..7fcb4467fb 100644
--- a/app/tools/Makefile.am
+++ b/app/tools/Makefile.am
@@ -256,7 +256,7 @@ CLEANFILES = $(gen_sources)
 
 xgen-tec: $(srcdir)/tools-enums.h $(GIMP_MKENUMS) Makefile.am
 	$(AM_V_GEN) $(GIMP_MKENUMS) \
-		--fhead "#include \"config.h\"\n#include <gio/gio.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"core/core-enums.h\"\n#include \"tools-enums.h\"\n#include \"gimp-intl.h\"" \
+		--fhead "#include \"stamp-tools-enums.h\"\n#include \"config.h\"\n#include <gio/gio.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"core/core-enums.h\"\n#include \"tools-enums.h\"\n#include \"gimp-intl.h\"" \
 		--fprod "\n/* enumerations from \"@basename@\" */" \
 		--vhead "GType\n@enum_name@_get_type (void)\n{\n  static const G@Type@Value values[] =\n  {" \
 		--vprod "    { @VALUENAME@, \"@VALUENAME@\", \"@valuenick@\" }," \
@@ -266,11 +266,14 @@ xgen-tec: $(srcdir)/tools-enums.h $(GIMP_MKENUMS) Makefile.am
 		--dtail "    { 0, NULL, NULL }\n  };\n\n  static GType type = 0;\n\n  if (G_UNLIKELY (! type))\n    {\n      type = g_@type@_register_static (\"@EnumName@\", values);\n      gimp_type_set_translation_context (type, \"@enumnick@\");\n      gimp_@type@_set_value_descriptions (type, descs);\n    }\n\n  return type;\n}\n" \
 		$< > $@
 
+stamp-tools-enums.h: xgen-tec
+	echo "/* Generated on `date`. */" > $@
+
 # copy the generated enum file back to the source directory only if it's
 # changed; otherwise, only update its timestamp, so that the recipe isn't
 # executed again on the next build, however, allow this to (harmlessly) fail,
 # to support building from a read-only source tree.
-$(srcdir)/tools-enums.c: xgen-tec
+$(srcdir)/tools-enums.c: xgen-tec stamp-tools-enums.h
 	$(AM_V_GEN) if ! cmp -s $< $@; then \
 		cp $< $@; \
 	else \
diff --git a/app/widgets/Makefile.am b/app/widgets/Makefile.am
index 201a6bc4c0..9422338dca 100644
--- a/app/widgets/Makefile.am
+++ b/app/widgets/Makefile.am
@@ -490,7 +490,7 @@ CLEANFILES = $(gen_sources)
 
 xgen-wec: $(srcdir)/widgets-enums.h $(GIMP_MKENUMS) Makefile.am
 	$(AM_V_GEN) $(GIMP_MKENUMS) \
-		--fhead "#include \"config.h\"\n#include <gtk/gtk.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"widgets-enums.h\"\n#include \"gimp-intl.h\"" \
+		--fhead "#include \"stamp-widgets-enums.h\"\n#include \"config.h\"\n#include <gtk/gtk.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"widgets-enums.h\"\n#include \"gimp-intl.h\"" \
 		--fprod "\n/* enumerations from \"@basename@\" */" \
 		--vhead "GType\n@enum_name@_get_type (void)\n{\n  static const G@Type@Value values[] =\n  {" \
 		--vprod "    { @VALUENAME@, \"@VALUENAME@\", \"@valuenick@\" }," \
@@ -500,11 +500,14 @@ xgen-wec: $(srcdir)/widgets-enums.h $(GIMP_MKENUMS) Makefile.am
 		--dtail "    { 0, NULL, NULL }\n  };\n\n  static GType type = 0;\n\n  if (G_UNLIKELY (! type))\n    {\n      type = g_@type@_register_static (\"@EnumName@\", values);\n      gimp_type_set_translation_context (type, \"@enumnick@\");\n      gimp_@type@_set_value_descriptions (type, descs);\n    }\n\n  return type;\n}\n" \
 		$< > $@
 
+stamp-widgets-enums.h: xgen-wec
+	echo "/* Generated on `date`. */" > $@
+
 # copy the generated enum file back to the source directory only if it's
 # changed; otherwise, only update its timestamp, so that the recipe isn't
 # executed again on the next build, however, allow this to (harmlessly) fail,
 # to support building from a read-only source tree.
-$(srcdir)/widgets-enums.c: xgen-wec
+$(srcdir)/widgets-enums.c: xgen-wec stamp-widgets-enums.h
 	$(AM_V_GEN) if ! cmp -s $< $@; then \
 		cp $< $@; \
 	else \
diff --git a/libgimpbase/Makefile.am b/libgimpbase/Makefile.am
index 79b480bcdb..7219446785 100644
--- a/libgimpbase/Makefile.am
+++ b/libgimpbase/Makefile.am
@@ -186,7 +186,7 @@ CLEANFILES = $(EXTRA_PROGRAMS) $(gen_sources)
 
 xgen-bec: $(srcdir)/gimpbaseenums.h $(GIMP_MKENUMS) Makefile.am
 	$(AM_V_GEN) $(GIMP_MKENUMS) \
-		--fhead "#include \"config.h\"\n#include <glib-object.h>\n#undef GIMP_DISABLE_DEPRECATED\n#include \"gimpbasetypes.h\"\n#include \"libgimp/libgimp-intl.h\"" \
+		--fhead "#include \"stamp-gimpbaseenums.h\"\n#include \"config.h\"\n#include <glib-object.h>\n#undef GIMP_DISABLE_DEPRECATED\n#include \"gimpbasetypes.h\"\n#include \"libgimp/libgimp-intl.h\"\n#include \"gimpbaseenums.h\"\n" \
 		--fprod "\n/* enumerations from \"@basename@\" */" \
 		--vhead "GType\n@enum_name@_get_type (void)\n{\n  static const G@Type@Value values[] =\n  {" \
 		--vprod "    { @VALUENAME@, \"@VALUENAME@\", \"@valuenick@\" }," \
@@ -196,11 +196,14 @@ xgen-bec: $(srcdir)/gimpbaseenums.h $(GIMP_MKENUMS) Makefile.am
 		--dtail "    { 0, NULL, NULL }\n  };\n\n  static GType type = 0;\n\n  if (G_UNLIKELY (! type))\n    {\n      type = g_@type@_register_static (\"@EnumName@\", values);\n      gimp_type_set_translation_domain (type, GETTEXT_PACKAGE \"-libgimp\");\n      gimp_type_set_translation_context (type, \"@enumnick@\");\n      gimp_@type@_set_value_descriptions (type, descs);\n    }\n\n  return type;\n}\n" \
 		$< > $@
 
+stamp-gimpbaseenums.h: xgen-bec
+	echo "/* Generated on `date`. */" > $@
+
 # copy the generated enum file back to the source directory only if it's
 # changed; otherwise, only update its timestamp, so that the recipe isn't
 # executed again on the next build, however, allow this to (harmlessly) fail,
 # to support building from a read-only source tree.
-$(srcdir)/gimpbaseenums.c: xgen-bec
+$(srcdir)/gimpbaseenums.c: xgen-bec stamp-gimpbaseenums.h
 	$(AM_V_GEN) if ! cmp -s $< $@; then \
 		cp $< $@; \
 	else \
@@ -210,7 +213,7 @@ $(srcdir)/gimpbaseenums.c: xgen-bec
 
 xgen-cec: $(srcdir)/gimpcompatenums.h $(GIMP_MKENUMS) Makefile.am
 	$(AM_V_GEN) $(GIMP_MKENUMS) \
-		--fhead "#include \"config.h\"\n#include <glib-object.h>\n#include \"gimpbasetypes.h\"\n#include \"gimpcompatenums.h\"\n#include \"libgimp/libgimp-intl.h\"" \
+		--fhead "#include \"stamp-gimpcompatenums.h\"\n#include \"config.h\"\n#include <glib-object.h>\n#include \"gimpbasetypes.h\"\n#include \"gimpcompatenums.h\"\n#include \"libgimp/libgimp-intl.h\"" \
 		--fprod "\n/* enumerations from \"@basename@\" */" \
 		--vhead "GType\n@enum_name@_get_type (void)\n{\n  static const G@Type@Value values[] =\n  {" \
 		--vprod "    { @VALUENAME@, \"@VALUENAME@\", \"@valuenick@\" }," \
@@ -220,11 +223,14 @@ xgen-cec: $(srcdir)/gimpcompatenums.h $(GIMP_MKENUMS) Makefile.am
 		--dtail "    { 0, NULL, NULL }\n  };\n\n  static GType type = 0;\n\n  if (G_UNLIKELY (! type))\n    {\n      type = g_@type@_register_static (\"@EnumName@\", values);\n      gimp_type_set_translation_domain (type, GETTEXT_PACKAGE \"-libgimp\");\n      gimp_type_set_translation_context (type, \"@enumnick@\");\n      gimp_@type@_set_value_descriptions (type, descs);\n    }\n\n  return type;\n}\n" \
 		$< > $@
 
+stamp-gimpcompatenums.h: xgen-cec
+	echo "/* Generated on `date`. */" > $@
+
 # copy the generated enum file back to the source directory only if it's
 # changed; otherwise, only update its timestamp, so that the recipe isn't
 # executed again on the next build, however, allow this to (harmlessly) fail,
 # to support building from a read-only source tree.
-$(srcdir)/gimpcompatenums.c: xgen-cec
+$(srcdir)/gimpcompatenums.c: xgen-cec stamp-gimpcompatenums.h
 	$(AM_V_GEN) if ! cmp -s $< $@; then \
 		cp $< $@; \
 	else \
diff --git a/libgimpconfig/Makefile.am b/libgimpconfig/Makefile.am
index 46eae24603..ce489fe696 100644
--- a/libgimpconfig/Makefile.am
+++ b/libgimpconfig/Makefile.am
@@ -109,7 +109,7 @@ CLEANFILES = $(gen_sources)
 
 xgen-cec: $(srcdir)/gimpconfigenums.h $(GIMP_MKENUMS) Makefile.am
 	$(AM_V_GEN) $(GIMP_MKENUMS) \
-		--fhead "#include \"config.h\"\n#include <gio/gio.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"gimpconfigenums.h\"\n#include \"libgimp/libgimp-intl.h\"" \
+		--fhead "#include \"stamp-gimpconfigenums.h\"\n#include \"config.h\"\n#include <gio/gio.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"gimpconfigenums.h\"\n#include \"libgimp/libgimp-intl.h\"" \
 		--fprod "\n/* enumerations from \"@basename@\" */" \
 		--vhead "GType\n@enum_name@_get_type (void)\n{\n  static const G@Type@Value values[] =\n  {" \
 		--vprod "    { @VALUENAME@, \"@VALUENAME@\", \"@valuenick@\" }," \
@@ -119,11 +119,14 @@ xgen-cec: $(srcdir)/gimpconfigenums.h $(GIMP_MKENUMS) Makefile.am
 		--dtail "    { 0, NULL, NULL }\n  };\n\n  static GType type = 0;\n\n  if (G_UNLIKELY (! type))\n    {\n      type = g_@type@_register_static (\"@EnumName@\", values);\n      gimp_type_set_translation_domain (type, GETTEXT_PACKAGE \"-libgimp\");\n      gimp_type_set_translation_context (type, \"@enumnick@\");\n      gimp_@type@_set_value_descriptions (type, descs);\n    }\n\n  return type;\n}\n" \
 		$< > $@
 
+stamp-gimpconfigenums.h: xgen-cec
+	echo "/* Generated on `date`. */" > $@
+
 # copy the generated enum file back to the source directory only if it's
 # changed; otherwise, only update its timestamp, so that the recipe isn't
 # executed again on the next build, however, allow this to (harmlessly) fail,
 # to support building from a read-only source tree.
-$(srcdir)/gimpconfigenums.c: xgen-cec
+$(srcdir)/gimpconfigenums.c: xgen-cec stamp-gimpconfigenums.h
 	$(AM_V_GEN) if ! cmp -s $< $@; then \
 		cp $< $@; \
 	else \
diff --git a/libgimpwidgets/Makefile.am b/libgimpwidgets/Makefile.am
index d9caa64854..70337db14d 100644
--- a/libgimpwidgets/Makefile.am
+++ b/libgimpwidgets/Makefile.am
@@ -180,7 +180,7 @@ CLEANFILES = $(gen_sources)
 
 xgen-wec: $(srcdir)/gimpwidgetsenums.h $(GIMP_MKENUMS) Makefile.am
 	$(AM_V_GEN) $(GIMP_MKENUMS) \
-		--fhead "#include \"config.h\"\n#include <gio/gio.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"gimpwidgetsenums.h\"\n#include \"libgimp/libgimp-intl.h\"" \
+		--fhead "#include \"stamp-gimpwidgetsenums.h\"\n#include \"config.h\"\n#include <gio/gio.h>\n#include \"libgimpbase/gimpbase.h\"\n#include \"gimpwidgetsenums.h\"\n#include \"libgimp/libgimp-intl.h\"" \
 		--fprod "\n/* enumerations from \"@basename@\" */" \
 		--vhead "GType\n@enum_name@_get_type (void)\n{\n  static const G@Type@Value values[] =\n  {" \
 		--vprod "    { @VALUENAME@, \"@VALUENAME@\", \"@valuenick@\" }," \
@@ -190,11 +190,14 @@ xgen-wec: $(srcdir)/gimpwidgetsenums.h $(GIMP_MKENUMS) Makefile.am
 		--dtail "    { 0, NULL, NULL }\n  };\n\n  static GType type = 0;\n\n  if (G_UNLIKELY (! type))\n    {\n      type = g_@type@_register_static (\"@EnumName@\", values);\n      gimp_type_set_translation_domain (type, GETTEXT_PACKAGE \"-libgimp\");\n      gimp_type_set_translation_context (type, \"@enumnick@\");\n      gimp_@type@_set_value_descriptions (type, descs);\n    }\n\n  return type;\n}\n" \
 		$< > $@
 
+stamp-gimpwidgetsenums.h: xgen-wec
+	echo "/* Generated on `date`. */" > $@
+
 # copy the generated enum file back to the source directory only if it's
 # changed; otherwise, only update its timestamp, so that the recipe isn't
 # executed again on the next build, however, allow this to (harmlessly) fail,
 # to support building from a read-only source tree.
-$(srcdir)/gimpwidgetsenums.c: xgen-wec
+$(srcdir)/gimpwidgetsenums.c: xgen-wec stamp-gimpwidgetsenums.h
 	$(AM_V_GEN) if ! cmp -s $< $@; then \
 		cp $< $@; \
 	else \