build: Remove unused rebuild_define gcc_toolchain arg

Nothing sets it.

https://codereview.chromium.org/1322523008 suggests it was added for some
NaCl reason, but NaCl is no more.

No behavior change.

Bug: 40511454
Change-Id: I7f71885222bb9587ffc0cabc6cc31183a200dd3d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6823849
Commit-Queue: Arthur Eubanks <aeubanks@google.com>
Reviewed-by: Arthur Eubanks <aeubanks@google.com>
Auto-Submit: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1498271}
NOKEYCHECK=True
GitOrigin-RevId: d971210b0f66b51cfe2b0e6aaf4e573a2dea1b30
1 file changed