Clang 12 doesn't support -Wno-bitwise-instead-of-logical,
so silence it with -Wno-unknown-warning-option.

GCC requires using GNU dialect of the C++ standard, using
optimizations (otherwise "always_inline" fails to inline),
and produces a lot of warnings that had to be silenced.
Signed-off-by: Piotr Sikora <piotrsikora@google.com>
Change-Id: I9ddd4f39dca2167b5b208dc2d0ba8e60030eddfc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3333635Reviewed-by: Victor Gomes <victorgomes@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78499}