common.gypi: When clang=1 on Windows, set CC to clang-cl

(See https://code.google.com/p/gyp/source/detail?r=1846 for
how GYP deals with this.)

BUG=82385

Review URL: https://codereview.chromium.org/147083011

git-svn-id: http://src.chromium.org/svn/trunk/src/build@247586 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

common.gypi

@@ -4770,7 +4770,7 @@
         ],
       },
     }],
-    ['clang==1', {
+    ['clang==1 and OS!="win"', {
       'make_global_settings': [
         ['CC', '<(make_clang_dir)/bin/clang'],
         ['CXX', '<(make_clang_dir)/bin/clang++'],
@@ -4778,6 +4778,12 @@
         ['CXX.host', '$(CXX)'],
       ],
     }],
+    ['clang==1 and OS=="win"', {
+      'make_global_settings': [
+        # On Windows, gyp's ninja generator only looks at CC.
+        ['CC', '<(make_clang_dir)/bin/clang-cl'],
+      ],
+    }],
     ['OS=="android" and clang==0', {
       # Hardcode the compiler names in the Makefile so that
       # it won't depend on the environment at make time.