https://bugs.gentoo.org/show_bug.cgi?id=526118
http://bugs.cinelerra-cv.org/ticket/1005

Author: Bernd Feige 

--- guicast/pngtoh.c	2015-01-29 13:41:01 +0000
+++ guicast/pngtoh.c	2015-01-29 13:41:07 +0000
@@ -148,4 +148,6 @@
 		fprintf(out, "};\n\n#endif\n");
 		fclose(out);
 	}
+
+	return 0;
 }