Add collation versions for FreeBSD.
On FreeBSD 13, use querylocale() to read the current version of libc
collations. Similar to commits
352f6f2d for Windows and
d5ac14f9 for
GNU/Linux.
Discussion: https://postgr.es/m/CAEepm%3D0uEQCpfq_%2BLYFBdArCe4Ot98t1aR4eYiYTe%3DyavQygiQ%40mail.gmail.com