Fix auto raw pointer deduction on linux

mojo/public/cpp/bindings/lib/message_header_validator.cc

Index: mojo/public/cpp/bindings/lib/message_header_validator.cc
diff --git a/mojo/public/cpp/bindings/lib/message_header_validator.cc b/mojo/public/cpp/bindings/lib/message_header_validator.cc
index 56be241ed62d4e2d6b0c18485cee425fcd8faffd..9f8c6278c07d0c520ad3ef11e3191d65307e4982 100644
--- a/mojo/public/cpp/bindings/lib/message_header_validator.cc
+++ b/mojo/public/cpp/bindings/lib/message_header_validator.cc
@@ -64,7 +64,7 @@ bool IsValidMessageHeader(const internal::MessageHeader* header,
   if (header->version < 2)
     return true;
 
-  auto header_v2 = static_cast<const internal::MessageHeaderV2*>(header);
+  auto* header_v2 = static_cast<const internal::MessageHeaderV2*>(header);
   // For the payload pointer:
   // - Check that the pointer can be safely decoded.
   // - Claim one byte that the pointer points to. It makes sure not only the