makepkg: allow specifying --pkg multiple times

Make this option additive, so that the following two operations are
equivalent:

  makepkg --pkg foo --pkg bar
  makepkg --pkg foo,bar

1 files changed, 1 insertions, 1 deletions

diff --git a/doc/makepkg.8.txt b/doc/makepkg.8.txt
index f80d7f20..57af98f7 100644
--- a/doc/makepkg.8.txt
+++ b/doc/makepkg.8.txt
@@ -154,7 +154,7 @@ Options
 
 *\--pkg <list>*::
 	Only build listed packages from a split package. Multiple packages should
-	be comma separated in the list.
+	be comma separated in the list. This option can be specified multiple times.
 
 *\--check*::
 	Run the check() function in the PKGBUILD, overriding the setting in