[roll pigweed] pw_boot_cortex_m: Add lld unused_space workaround

The bloaty unused_space symbols in basic_cortex_m.ld are not compatible
with lld (llvm linker) which is an obstacle to easily building with
clang-based toolchains (including //pw_toolchain/arm_clang). This
change adds a workaround to allow disabling those symbols when
PW_BOOT_WORKAROUND_DISABLE_UNUSED_SPACE evaluates to True.

Hopefully this workaround will be short-lived and deprecated by a fix
for unused_space in lld.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/106910

https://pigweed.googlesource.com/pigweed/pigweed
pigweed Rolled-Commits: 15ed2fce7c41f57..855f2633b08fb3e
Roller-URL: https://ci.chromium.org/b/8805647088010134129
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: If00845050c01aa91e41387e2f447291c4d38646f
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/zephyr-integration/+/106914
Bot-Commit: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
Commit-Queue: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
1 file changed
tree: d476c9b2a44d584bc8aca6f8beaa1a2041f8392e
  1. .gitmodules
  2. test.sh