libmakepkg: don't save/set/restore extglob in bash [[ tests

Since bash 4.1 extglobs can be used within [[ ... ]] regardless of
whether the shopt is set. Our configure.ac requires bash 4.1.0 at a
minimum for pacman scripts.

Signed-off-by: Eli Schwartz <eschwartz@archlinux.org>
Signed-off-by: Allan McRae <allan@archlinux.org>

scripts/libmakepkg/util/util.sh.in

@@ -42,15 +42,10 @@ is_array() {
 	local v=$1
 	local ret=1
 
-	# this function requires extglob - save current status to restore later
-	local shellopts=$(shopt -p extglob)
-	shopt -s extglob
-
 	if [[ $(declare -p "$v") == declare\ -*([[:alnum:]])a*([[:alnum:]])\ * ]]; then
 		ret=0
 	fi
 
-	eval "$shellopts"
 	return $ret
 }