Set -fmsc-version appropriately for clang on VS2015

build/config/compiler/BUILD.gn

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/android/config.gni")
 import("//build/config/chrome_build.gni")
 if (current_cpu == "arm") {
   import("//build/config/arm.gni")
 }
 if (current_cpu == "mipsel" || current_cpu == "mips64el") {
@@ skipping 90 matching lines @@
       "/Gy",  # Enable function-level linking.
       "/GS",  # Enable buffer security checking.
       "/FS",  # Preserve previous PDB behavior.
     ]
 
     # Building with Clang on Windows is a work in progress and very
     # experimental. See crbug.com/82385.
     # Keep this in sync with the similar block in build/common.gypi
     if (is_clang) {
       cflags += [
-        "-fmsc-version=1800",
-
         # Many files use intrinsics without including this header.
         # TODO(hans): Fix those files, or move this to sub-GYPs.
         "/FIIntrin.h",
       ]
+
+      if (visual_studio_version == "2013") {

[hans, 2015/06/10 18:05:38]

This buildbot seems sad because of this:
http://build.chromium.org/p/chromium.fyi/builders/CrWinClang64%28dbg%29/build...

+        cflags += [ "-fmsc-version=1800" ]
+      } else if (visual_studio_version == "2015") {
+        cflags += [ "-fmsc-version=1900" ]
+      }
+
       if (current_cpu == "x86") {
         cflags += [
           "/fallback",
           "-m32",
         ]
       } else {
         cflags += [ "-m64" ]
       }
     }
   } else {
@@ skipping 1121 matching lines @@
       cflags += [ "-gsplit-dwarf" ]
     }
   }
 }
 
 config("no_symbols") {
   if (!is_win) {
     cflags = [ "-g0" ]
   }
 }