New comment by Duncaen on void-packages repository

https://github.com/void-linux/void-packages/issues/50847#issuecomment-2171676420

Comment:
It should fallback to some tempdir defined by libc.
```
/usr/include/stdio.h:# define P_tmpdir  "/tmp"
```

https://github.com/void-linux/xbps/blob/e82437f1d34facc0744f628938a1b3835dc7d963/lib/package_script.c#L71