[gegl] build: use fuller path to argvs extract

[Øyvind "pippin" Kolås <ok src gnome org>]

commit 77c4224f10b459a296697c2af62e513e55ead68f
Author: Øyvind Kolås <pippin gimp org>
Date:   Wed Jan 16 17:07:20 2019 +0100

    build: use fuller path to argvs extract

 bin/Makefile.am | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/bin/Makefile.am b/bin/Makefile.am
index cbe075803..723fe7e6f 100644
--- a/bin/Makefile.am
+++ b/bin/Makefile.am
@@ -47,7 +47,7 @@ gegl_SOURCES =                        \
 
 argvs-commands.inc: gegl.c ui.c argvs.c Makefile
        @echo " GEN" $@
-       @$(top_srcdir)/tools/argvs_extract.sh *.c > argvs-commands.inc
+       @$(top_srcdir)/tools/argvs_extract.sh $(top_srcdir)/bin/*.c > argvs-commands.inc
 
 if HAVE_MRG
 if HAVE_GEXIV2