abuild: don't set and reset xterm title when splitting subpkg

it's annoying flickering, and results the title being unset for
the time when last split is executed and packages are created.

abuild.in

@@ -68,7 +68,7 @@ cross_compiling() {
 
 cleanup() {
 	local i=
-	set_xterm_title ""
+	[ -z "$subpkgdir" ] && set_xterm_title ""
 	if [ -n "$CLEANUP_FILES" ]; then
 		rm -f $CLEANUP_FILES
 	fi
@@ -2271,7 +2271,7 @@ pkgdir="$pkgbasedir/$pkgname"
 controldir="$pkgbasedir"/.control.${subpkgname:-$pkgname}
 
 trap 'die "Aborted by user"' INT
-set_xterm_title "abuild: $pkgname"
+[ -z "$subpkgdir" ] && set_xterm_title "abuild: $pkgname"
 
 if [ -z "$1" ]; then
 	set all