Hi,

attached is a v3 of the musl-cross-make clang build patch.

Changes from v2:

* Update default TARGETS list
* Add some sane default -mfpu options
* Support target specific config by setting TARGET_CONFIG_<target> variable
* Drop spurious musl patch - this was caused by missing -mfpu options
* Switch to ninja

I don't like depending on ninja. Unfortunately there appear to be
numerous parallel make dependency bugs somewhere between cmake and
make which causes parallel "Unix Makefiles" builds to spuriously fail
with the versions of cmake/make on my development machine. cmake+ninja
has never failed for me.

I haven't submitted the three patches included here yet as I'm waiting
for feedback on the overall direction of this work.

I also have some extra patches which make lld & llvm-objcopy usable in
my embedded projects but have not included them here as they're under
upstream review.

Changes from v1:

* Install clang-resource-headers (fixes missing stdatomic.h, etc.)
* Fix installed symlinks (fixes missing cc, c++, cpp)
* Statically link libunwind and libc++abi into libc++.a and libc++.so
* Updated patch for armv7m clang VFP asm crash
* Support setting COMPILER from config.mak
* Support target specific musl config by setting MUSL_CONFIG_<target> variable

Best regards,

Patrick