Initial work to get clang building ARM firmware.
Current state:
- Does not work on Windows; no clang toolchain yet.
- Almost all tests pass.
- FreeListHeap tests that don't zero-initilize the buffer fail in qemu
and crash on STM32F429I-DISC1. (pwbug/315)
Change-Id: I39559511f19571c26930a868406d6ee1b514c412
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/13144
Commit-Queue: Armando Montanez <amontanez@google.com>
Reviewed-by: Keir Mierle <keir@google.com>
Reviewed-by: Ewout van Bekkum <ewout@google.com>
Reviewed-by: Alexei Frolov <frolv@google.com>
Pigweed-Auto-Submit: Armando Montanez <amontanez@google.com>