--- a/dom/canvas/moz.build
+++ b/dom/canvas/moz.build
@@ -178,8 +178,13 @@ LOCAL_INCLUDES += [
     '/layout/xul',
     '/media/libyuv/include',
 ]
 
 CXXFLAGS += CONFIG['MOZ_CAIRO_CFLAGS']
 CXXFLAGS += CONFIG['TK_CFLAGS']
 
 LOCAL_INCLUDES += CONFIG['SKIA_INCLUDES']
+
+if CONFIG['_MSC_VER']:
+    # This is intended as a temporary hack to support building with VS2015.
+    # 'type cast': conversion from '*' to '*' of greater size
+    CXXFLAGS += ['-wd4312']
\ No newline at end of file

--- a/dom/media/moz.build
+++ b/dom/media/moz.build
@@ -320,9 +320,14 @@ if CONFIG['MOZ_GONK_MEDIACODEC']:
 include('/ipc/chromium/chromium-config.mozbuild')
 
 # Suppress some GCC warnings being treated as errors:
 #  - about attributes on forward declarations for types that are already
 #    defined, which complains about an important MOZ_EXPORT for android::AString
 if CONFIG['GNU_CC']:
   CXXFLAGS += ['-Wno-error=attributes']
 
+if CONFIG['_MSC_VER']:
+    # This is intended as a temporary hack to support building with VS2015.
+    # 'type cast': conversion from '*' to '*' of greater size
+    CXXFLAGS += ['-wd4312']
+
 FINAL_LIBRARY = 'xul'