argparse: gpgrt_fconcat to get the SYSCONFDIR.
* src/stringutils.c (_gpgrt_fconcat): New internal function. * src/argparse.c (_gpgrt_argparser): Use it.
This fixes the conf files default also for Windows.
Updates-commmit: a9fc729253eec88f56d810bd2a8edd327267c5b4
- GnuPG-bug-id: T7894