Using > or < in the provides array is wrong so make it cause an error.
Fixes FS#12540.
Also, use bash substitution rather than spawning new processes where
possible in the error checking. Move split package detection to a
better position.
Signed-off-by: Allan McRae <allan@archlinux.org>
[Dan: backport to maint]
Signed-off-by: Dan McGee <dan@archlinux.org>