Mac on aarch64 uses posix_memmap.c os_mmap which doesn't do anything with the flag MMAP_MAP_32BIT for that build so this condition ends up asserting unless the mapping ends up in the first 4 gigs worth of addressable space. Thsi PR changes to call os_mmap with MMAP_MAP_32BIT flag only when the target is x86-64 or riscv64, and the macro __APPLE__ isn't enabled. The behavior is similar to what the posix os_mmap does.