New review comment by ahesford on void-packages repository

https://github.com/void-linux/void-packages/pull/38911#discussion_r955356365

Comment:
```suggestion
	for f in ${XBPS_CROSS_BASE}/${py3_lib}/_sysconfigdata_*; do
		[ -f "$f" ] || continue
		f=${f##*/}
		_PYTHON_SYSCONFIGDATA_NAME=${f%.py}
	done
	[ -n "$_PYTHON_SYSCONFIGDATA_NAME" ] && export _PYTHON_SYSCONFIGDATA_NAME
```
This loop has always kind of bugged me. I've always wondered whether we should break after the first match or continue looping to pick the last match. (In practice, there is probably only one, so it shouldn't matter, but still...)

Without taking a position on that matter, let's at least confirm the file exists to avoid picking up a null match and make sure we picked something before exporting it.