clang/win: Build chromium code without -Wno-incompatible-pointer-types.

third_party/libxml/BUILD.gn

Index: third_party/libxml/BUILD.gn
diff --git a/third_party/libxml/BUILD.gn b/third_party/libxml/BUILD.gn
index bca823a89c33bb8acf04aa3f3c528cd7104c7755..1f10dee5889d545ecb672337e083253c172e51bb 100644
--- a/third_party/libxml/BUILD.gn
+++ b/third_party/libxml/BUILD.gn
@@ -187,6 +187,10 @@ static_library("libxml") {
       cflags += [
         # libxml casts from int to long to void*.
         "-Wno-int-to-void-pointer-cast",
+
+        # libxml passes a volatile LPCRITICAL_SECTION* to a function expecting
+        # a void* volatile*.
+        "-Wno-incompatible-pointer-types",
       ]
     }
   }