Bug 1256514 - Disable C4577 to unblock compilation on VS2015; r=poiru

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. That being said, the warning occurs in 3rd party ICU
code. So I'm not sure what my options are for fixing this.

MozReview-Commit-ID: 9gOSotjaQsN

--HG--
extra : rebase_source : c1a6c51bcdd4e1a882f371e7beba4f88d5c059a4

intl/unicharutil/util/internal/moz.build

@@ -23,3 +23,9 @@ if CONFIG['ENABLE_INTL_API']:
     LOCAL_INCLUDES += CONFIG['MOZ_ICU_INCLUDES']
 
 DIST_INSTALL = True
+
+if CONFIG['_MSC_VER']:
+    # This is intended as a temporary hack to support building with VS2015.
+    # 'noexcept' used with no exception handling mode specified;
+    # termination on exception is not guaranteed. Specify /EHsc
+    CXXFLAGS += ['-wd4577']