work around linker-error when building on the Mac



git-svn-id: http://skia.googlecode.com/svn/trunk@930 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/ports/SkFontHost_FreeType.cpp b/src/ports/SkFontHost_FreeType.cpp
index 5fb3245..96cdcca 100644
--- a/src/ports/SkFontHost_FreeType.cpp
+++ b/src/ports/SkFontHost_FreeType.cpp
@@ -346,6 +346,9 @@
 // static
 SkAdvancedTypefaceMetrics* SkFontHost::GetAdvancedTypefaceMetrics(
         uint32_t fontID, bool perGlyphInfo) {
+#if defined(SK_BUILD_FOR_MAC)
+    return NULL;
+#else
     SkAutoMutexAcquire ac(gFTMutex);
     FT_Library libInit = NULL;
     if (gFTCount == 0) {
@@ -510,6 +513,7 @@
 
     unref_ft_face(face);
     return info;
+#endif
 }
 ///////////////////////////////////////////////////////////////////////////