gbm: automake: add

VISIBILITY_CFLAGS

Currently the library exports every symbol imaginable,
rather than the ones defined by the API.

Note: This may cause issues for libraries that are linking
agaist libgbm's internals.

Cc: Kristian Høgsberg <krh@bitplanet.net>
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>

src/gbm/Makefile.am

@@ -11,7 +11,8 @@ AM_CFLAGS = \
 	-I$(top_srcdir)/src/gbm/main \
 	$(LIBKMS_CFLAGS) \
 	$(DLOPEN_CFLAGS) \
-	$(DEFINES)
+	$(DEFINES) \
+	$(VISIBILITY_CFLAGS)
 
 lib_LTLIBRARIES = libgbm.la
 include_HEADERS = main/gbm.h