makepkg: detect incorrect usage of provides array

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>

1 files changed, 3 insertions, 1 deletions

diff --git a/doc/PKGBUILD.5.txt b/doc/PKGBUILD.5.txt
index 22c56be3..b0f2bdb6 100644
--- a/doc/PKGBUILD.5.txt
+++ b/doc/PKGBUILD.5.txt
@@ -160,7 +160,9 @@ name. The syntax is: `$$source=('filename::url')$$`
 	depend on 'cron' rather than 'dcron OR fcron'.
 	Versioned provisions are also possible, in the 'name=version' format.
 	For example, dcron can provide 'cron=2.0' to satisfy the 'cron>=2.0'
-	dependency of other packages.
+	dependency of other packages. Provisions involving the '>' and '<'
+	operators are invalid as only specifc versions of a package may be
+	provided.
 
 *replaces (array)*::
 	An array of packages that this package should replace, and can be used