[gnome-builder] egg: link to libm for ceil in three-grid

[Christian Hergert <chergert src gnome org>]

commit a7da64d99bb8c217ec79b29ef2b950091242230f
Author: Marinus Schraal <mschraal src gnome org>
Date:   Tue Sep 20 16:10:43 2016 +0200

    egg: link to libm for ceil in three-grid
    
    https://bugzilla.gnome.org/show_bug.cgi?id=771725

 contrib/egg/Makefile.am |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/contrib/egg/Makefile.am b/contrib/egg/Makefile.am
index 0f040fc..4aee7a4 100644
--- a/contrib/egg/Makefile.am
+++ b/contrib/egg/Makefile.am
@@ -93,6 +93,7 @@ libegg_private_la_CFLAGS = \
 libegg_private_la_LIBADD = \
        $(EGG_LIBS) \
        $(SHM_LIB) \
+       $(LIBM) \
        $(NULL)