Maint: gdbhelpers: relicense, add support for strcmp-unaware settings

...that happens to be the case, e.g., in FreeBSD, which would previously
make pcmk-follow-daemon choke there.

At that opportunity, the file gets relicensed to "FSFAP", which now
appears substantially more reasonable for such auxiliary/supportive bits,
and move to the formerly anticipated top-level directory meant to carry
files mostly useful for maintenance (as its name suggests).