Closed issue by st3r4g on void-packages repository

https://github.com/void-linux/void-packages/issues/15208

Description:
### Steps to reproduce the behavior
* Remove `etc/conf` and `$HOME/.xbps-src.conf`
* `./xbps-src -N chroot`

`grep: : No such file or directory`

Could be solved by adding the `-s` flag to `grep` in `common/xbps-src/shutils/chroot.sh` or adding a check for `$XBPS_CONFIG_FILE`