Breaks pw_cc_* internal macros out into a seperate directory so that
they can be used by other macros in the repository. This allows
pw_cc_fuzz_test to use the same backend macros as those defined in
pw_build.
No-Docs-Update-Reason: Fixes build macros.
Change-Id: I326640c328b2619b711b03ae290e4942ef91807a
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/57360
Reviewed-by: Keir Mierle <keir@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>
Pigweed-Auto-Submit: Rob Mohr <mohrr@google.com>
