[build] more Makefile.am.{enums,marshal} fixes for out of tree builds

for the marshal files $(srcdir) was getting prefixed twice since my last
commit (2cc88f1140) since it was already being prefixed including
Makefile.am.  The problem with prefixing it in the includer file though is
that the Make variable substitutions like :.list=.h mean we end up
generating into the $(srcdir).  This removes the prefix added in
clutter/Makefile.am

We were also missing a $(srcdir) prefix when setting EXTRA_DIST

build/autotools/Makefile.am.enums

@@ -21,7 +21,7 @@ enum_tmpl_c=$(glib_enum_c:.c=.c.in)
 CLEANFILES += stamp-enum-types
 DISTCLEANFILES += $(glib_enum_h) $(glib_enum_c)
 BUILT_SOURCES += $(glib_enum_h) $(glib_enum_c)
-EXTRA_DIST += $(enum_tmpl_h) $(enum_tmpl_c)
+EXTRA_DIST += $(srcdir)/$(enum_tmpl_h) $(srcdir)/$(enum_tmpl_c)
 
 stamp-enum-types: $(glib_enum_headers)
 	$(QUIET_GEN)$(GLIB_MKENUMS) \

build/autotools/Makefile.am.marshal

@@ -20,7 +20,7 @@ marshal_c = $(glib_marshal_list:.list=.c)
 CLEANFILES += stamp-marshal
 DISTCLEANFILES += $(marshal_h) $(marshal_c)
 BUILT_SOURCES += $(marshal_h) $(marshal_c)
-EXTRA_DIST += $(glib_marshal_list)
+EXTRA_DIST += $(srcdir)/$(glib_marshal_list)
 
 stamp-marshal: $(glib_marshal_list)
 	$(QUIET_GEN)$(GLIB_GENMARSHAL) \
@@ -42,3 +42,4 @@ $(marshal_c): $(marshal_h)
 	$(srcdir)/$(glib_marshal_list)) > xgen-mc \
 	&& cp xgen-mc $(marshal_c) \
 	&& rm -f xgen-mc
+

clutter/Makefile.am

@@ -103,7 +103,7 @@ source_h =					\
 	$(NULL)
 
 # glib-genmarshal rules
-glib_marshal_list = $(srcdir)/clutter-marshal.list
+glib_marshal_list = clutter-marshal.list
 glib_marshal_prefix = clutter_marshal
 include $(top_srcdir)/build/autotools/Makefile.am.marshal