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

third_party/zlib/BUILD.gn

Index: third_party/zlib/BUILD.gn
diff --git a/third_party/zlib/BUILD.gn b/third_party/zlib/BUILD.gn
index a1317f222908687b218ae7724bd6a4677669b79e..0d592189c8b1811dd565f946fb1901ac6dbe548b 100644
--- a/third_party/zlib/BUILD.gn
+++ b/third_party/zlib/BUILD.gn
@@ -67,6 +67,13 @@ static_library("zlib") {
 
   if (!is_ios && (current_cpu == "x86" || current_cpu == "x64")) {
     sources += [ "x86.c" ]
+
+    config("zlib_warnings") {
+      if (is_clang) {
+        cflags = [ "-Wno-incompatible-pointer-types" ]
+      }
+    }
+    configs += [ ":zlib_warnings" ]
   }
 
   configs -= [ "//build/config/compiler:chromium_code" ]