Merge pull request #1137 from mapbox/clang-3.5

Fix build failure when using clang-3.5 on Linux

src/mbgl/text/collision.hpp

@@ -4,6 +4,7 @@
 #include <mbgl/text/types.hpp>
 
 #pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-function"
 #pragma GCC diagnostic ignored "-Wunused-parameter"
 #pragma GCC diagnostic ignored "-Wunused-variable"
 #pragma GCC diagnostic ignored "-Wshadow"