[dia] cgm: add header to Makefile.am (found by make distcheck)

[Hans Breuer <hans src gnome org>]

commit 2b073d9a1c3967465c2f0d13e4ebf4d0af000f46
Author: Hans Breuer <hans breuer org>
Date:   Sun Aug 31 19:10:35 2014 +0200

    cgm: add header to Makefile.am (found by make distcheck)

 plug-ins/cgm/Makefile.am |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/plug-ins/cgm/Makefile.am b/plug-ins/cgm/Makefile.am
index 8054728..ed3b7a6 100644
--- a/plug-ins/cgm/Makefile.am
+++ b/plug-ins/cgm/Makefile.am
@@ -2,7 +2,7 @@
 
 pkglib_LTLIBRARIES = libcgm_filter.la
 
-libcgm_filter_la_SOURCES = cgm.c
+libcgm_filter_la_SOURCES = cgm.c cgm.h
 
 libcgm_filter_la_LDFLAGS = -export-dynamic -module -avoid-version $(NO_UNDEFINED)