Bug 1256501 - Disable C4312 to unblock compilation on VS2015; r?aklotz As part of unblocking building with VS2015u1 in automation, I'm mass disabling compiler warnings that are turned into errors. This is not the preferred mechanism to fix compilation warnings. So hopefully this patch never lands because someone insists of fixing the underlying problem instead. But if it does land, hopefully the workaround is only temporary. MozReview-Commit-ID: FoYEsdZxi28

--- a/widget/windows/moz.build
+++ b/widget/windows/moz.build
@@ -104,8 +104,13 @@ for var in ('MOZ_ENABLE_D3D10_LAYER'):
 
 RESFILE = 'widget.res'
 
 CXXFLAGS += CONFIG['MOZ_CAIRO_CFLAGS']
 
 OS_LIBS += [
     'rpcrt4',
 ]
+
+if CONFIG['_MSC_VER']:
+    # This is intended as a temporary hack to support building with VS2015.
+    # 'reinterpret_cast': conversion from 'int' to 'HANDLE' of greater size
+    CXXFLAGS += ['-wd4312']