The -march flag for compiling C libraries (compiler-rt, picolibc) was
hardcoded to rv32imac for all riscv32 targets. This is incorrect for
targets that lack the atomic extension, such as ESP32-C3 (rv32imc) and
TKey (rv32iczmmul).
Extract the -march value from the target's cflags when available,
falling back to the previous defaults (rv32imac, rv64gc) for targets
that don't override it.
Fixes#5114
Signed-off-by: deadprogram <ron@hybridgroup.com>
deadprogram
1fadd0e772