New review comment by TinfoilSubmarine on void-packages repository

https://github.com/void-linux/void-packages/pull/36330#discussion_r835289448

Comment:
Need to patch out tests if CROSS_BUILD:
```
post_patch() {
        if [ "$CROSS_BUILD" ]; then
                vsed -e "/\(fmt_lld\|fmt_i64d\|fmt_i64lld\)/d" -i libqpdf/CMakeLists.txt
        fi
}
```