The mips64 port requires 'struct stat' conversion due to incorrect
32-bit fields where time_t should be in the kernel version of the
structure. The mips64 port performs the correct translation for stat,
fstat, and lstat syscalls, but omits any special handling for fstatat.
I'm planning to commit the attached patch to fix it; casual testing
(linking toybox against the resulting libc and running toybox ls)
seems to show it works.

I also plan to remove (in a separate commit) the old __clang__ check
that suppresses inline syscalls on mips and mips64; it seems the
relevant bug in clang was fixed long before clang was safe for
compiling musl.

Rich