Add necessary flags for building MSVC binding

Using C++14 mode is necessary because MSVC's std headers include some
C++14 syntax. "utility" is converted to "/utility" to exclude MSVC's
"xutility" header.

ports/geckolib/gecko_bindings/tools/regen.py

@@ -21,7 +21,7 @@
     # Flags common for all the targets.
     COMMON_BUILD_KEY: {
         "flags": [
-            "-x", "c++", "-std=gnu++0x",
+            "-x", "c++", "-std=c++14",
             "-allow-unknown-types", "-no-bitfield-methods",
             "-no-type-renaming", "-no-namespaced-constants",
             "-DTRACING=1", "-DIMPL_LIBXUL", "-DMOZ_STYLO_BINDINGS=1",
@@ -71,10 +71,11 @@
             "gfxFontFamilyList.h", "gfxFontFeatures.h", "imgRequestProxy.h",
             "nsIRequest.h", "imgIRequest.h", "CounterStyleManager.h",
             "nsStyleConsts.h", "nsCSSValue.h", "SheetType.h", "nsIPrincipal.h",
-            "nsDataHashtable.h", "nsCSSScanner.h", "utility", "nsTArray",
+            "nsDataHashtable.h", "nsCSSScanner.h", "nsTArray",
             "pair", "SheetParsingMode.h", "StaticPtr.h", "nsProxyRelease.h",
             "mozilla/dom/AnimationEffectReadOnlyBinding.h",
             "/Types.h",   # <- Disallow UnionTypes.h
+            "/utility",   # <- Disallow xutility
             "nsINode.h",  # <- For `NodeFlags`.
         ],
         "blacklist": [
@@ -140,6 +141,27 @@ def platform_dependent_defines():
         ret.append("-DOS_LINUX=1")
     elif system == "Darwin":
         ret.append("-DOS_MACOSX=1")
+    elif system == "Windows":
+        ret.append("-DOS_WIN=1")
+        ret.append("-DWIN32=1")
+        ret.append("-use-msvc-mangling")
+        msvc_platform = os.environ["PLATFORM"]
+        if msvc_platform == "X86":
+            ret.append("--target=i686-pc-win32")
+        elif msvc_platform == "X64":
+            ret.append("--target=x86_64-pc-win32")
+        else:
+            raise Exception("Only MSVC builds are supported on Windows")
+        # For compatibility with MSVC 2015
+        ret.append("-fms-compatibility-version=19")
+        # To enable the builtin __builtin_offsetof so that CRT wouldn't
+        # use reinterpret_cast in offsetof() which is not allowed inside
+        # static_assert().
+        ret.append("-D_CRT_USE_BUILTIN_OFFSETOF")
+        # Enable hidden attribute (which is not supported by MSVC and
+        # thus not enabled by default with a MSVC-compatibile build)
+        # to exclude hidden symbols from the generated file.
+        ret.append("-DHAVE_VISIBILITY_HIDDEN_ATTRIBUTE=1")
     else:
         raise Exception("Unknown platform")