configure.ac: test for common byte-swapping functions
configure.ac: test for common byte-swapping functions

Test for a variety of common byte-swapping functions.

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

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