xbps-src: chroot: do nothing if we are already in the chroot.

common/xbps-src/shutils/chroot.sh

@@ -155,7 +155,7 @@ chroot_sync_repos() {
 chroot_handler() {
     local action="$1" pkg="$2" rv=0 arg= _envargs= _chargs=
 
-    if [ -z "$CHROOT_READY" ]; then
+    if [ -n "$IN_CHROOT" -o -z "$CHROOT_READY" ]; then
         return 0
     fi
     # Debian uses /run/shm instead...