As with the other ac_cv_func_posix_* functions, this is specific to the
libc and not the architecture.
(From OE-Core rev: 2e190f4e443d6c6e44c3f775ff74e8d14e880a59)
Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>