makechrootpkg: Avoid having code floating around outside of a function.

This means wrapping variable initialization in init_variables(), and the
main program routine in main().

I did NOT put `shopt -s nullglob` in to a function.

It make make sense to move init_variables() down into the main()
function, instead of having it as a separate function up top (if this
done, then the `-g` flag passed to `declare` in init_variables() can
be dropped).  However, in interest of keeping the `diff -w` small, and
merges/rebases simpler, this isn't done here.

makechrootpkg.in

@@ -15,6 +15,7 @@ m4_include(lib/archroot.sh)
 
 shopt -s nullglob
 
+init_variables() {
 	default_makepkg_args=(-s --noconfirm -L --holdver)
 	makepkg_args=("${default_makepkg_args[@]}")
 	repack=false
@@ -25,8 +26,8 @@ temp_chroot=false
 	chrootdir=
 	passeddir=
 	makepkg_user=
-declare -a install_pkgs
-declare -i ret=0
+	declare -ga install_pkgs
+	declare -gi ret=0
 
 	bindmounts_ro=()
 	bindmounts_rw=()
@@ -35,6 +36,7 @@ copy=$USER
 	[[ -n ${SUDO_USER:-} ]] && copy=$SUDO_USER
 	[[ -z "$copy" || $copy = root ]] && copy=copy
 	src_owner=${SUDO_USER:-$USER}
+}
 
 usage() {
 	echo "Usage: ${0##*/} [options] -r <chrootdir> [--] [makepkg args]"
@@ -308,6 +310,9 @@ move_products() {
 }
 # }}}
 
+main() {
+	init_variables
+
 	while getopts 'hcur:I:l:nTD:d:U:' arg; do
 		case "$arg" in
 			c) clean_first=true ;;
@@ -414,3 +419,6 @@ if (( ret != 0 )); then
 	else
 		true
 	fi
+}
+
+main "$@"