diff --git a/src/styles/Makefile.am b/src/styles/Makefile.am
index f66daa60..bf115db3 100644
--- a/src/styles/Makefile.am
+++ b/src/styles/Makefile.am
@@ -18,6 +18,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 
+AUTOMAKE_OPTIONS = -Wno-portability
 SASSFLAGS = --style=compressed --no-cache
 AUTOPREFIXER_BROWSER_SUPPORT := "> 1%, last 2 versions, Firefox ESR, Opera 12.1"
 STATIC = ../../static