DEPs-ing in tools/clang rather than relying on outdated scripts.

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 45c8e34c084a48396934b2482808c58f90af18fd..43a4a7931ef4ee3df07247bb737f0a4ea16ae3ef 100644
--- a/build/config/compiler/BUILD.gn
+++ b/build/config/compiler/BUILD.gn
@@ -849,6 +849,12 @@ if (is_clang) {
 
       # TODO(smklein): Consider enabling this once not broken by third party
       "-Wno-bitfield-width",
+
+      # TODO(smklein): Remove once not broken by base.
+      "-Wno-expansion-to-defined",
+
+      # TODO(smklein): Remove once not broken by third party.
+      "-Wno-constant-conversion",
     ]
   }
 }