Revert of win/clang: Roll clang 239674:242130

build/config/compiler/BUILD.gn

Index: build/config/compiler/BUILD.gn
diff --git a/build/config/compiler/BUILD.gn b/build/config/compiler/BUILD.gn
index 586b1a5989228a80fc997572ab1c815d03481908..2f9f558c1f59ba137ef99aee414a7ca7e42846ff 100644
--- a/build/config/compiler/BUILD.gn
+++ b/build/config/compiler/BUILD.gn
@@ -916,10 +916,18 @@
     default_warning_flags += [
       # TODO(hans): Get this cleaned up, http://crbug.com/428099
       "-Wno-inconsistent-missing-override",
-
-      # TODO(thakis): Enable this, crbug.com/507717
-      "-Wno-shift-negative-value",
-    ]
+    ]
+
+    if (exec_script("//tools/clang/scripts/update.py",
+                    [ "--print-revision" ],
+                    "trim string") != "239674-1") {
+      default_warning_flags += [
+        # TODO(thakis): Move this into outer if once clang is rolled far enough
+        # that the pinned clang understands this flag.
+        # TODO(thakis): Enable this, crbug.com/507717
+        "-Wno-shift-negative-value",
+      ]
+    }
   }
 }