Refactor incompatible pointer type to a config

It makes it easier to fix the logic in a single place,
for example when porting a new cross compiler.

BUG=None
TEST=gn gen generates the same ninja files.
TBR=brettw@chromium.org

Review URL: https://codereview.chromium.org/1233913002

Cr-Original-Commit-Position: refs/heads/master@{#339257}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: d68ffb8b4bf017ec49d2a6fbb46b9e46299c4f16
1 file changed