Older macOS versions (macOS 12.2 at least) don't support this
option, while newer macOS versions do support it (macOS 12.6).
The solution is based on https://stackoverflow.com/a/1116890/3115956,
but simplified for this usecase.
Provide wrappers named <triplet>-gcc and <triplet>-g++ as well,
to ease cross compilation with e.g. autotools, to allow just
specifying --host=<triplet>.
Provide wrappers for objdump and ld that provide specific output
that autotools look for.
Provide <triplet>-strip as a symlink to /bin/true, since there is
no strip tool available yet (and llvm-objcopy doesn't support
COFF yet).