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

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index cfe0d76e44b1b8bf5a8570164495abd6adbc2745..02844830b97eed639f4e960ba004d8875c57c737 100644
--- a/build/common.gypi
+++ b/build/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.