configure.ac: use AC_FUNC_MMAP instead of AC_CHECK_FUNCS(mmap)
configure.ac: use AC_FUNC_MMAP instead of AC_CHECK_FUNCS(mmap)

There are a couple of extra checks in autoconf for mmap, supposedly.

Signed-off-by: H. Peter Anvin <8a453bad9912ffe59bc0f0b8abe03df9be19379e@zytor.com>

techkey/nasm,techkey/nasm,techkey/nasm,techkey/nasm,techkey/nasm