Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

Add collation version support to querylocale(3).

Provide a way to ask for an opaque version string for a locale_t, so
that potential changes in sort order can be detected. Similar to
ICU's ucol_getVersion() and Windows' GetNLSVersionEx(), this API is
intended to allow databases to detect when text order-based indexes
might need to be rebuilt.

The CLDR version is extracted from CLDR source data by the Makefile
under tools/tools/locale, written into the machine-generated Makefile
under shared/colldef, passed to localedef -V, and then written into
LC_COLLATE file headers. The initial version is 34.0.
tools/tools/locale was recently updated to pull down 35.0, but the
output hasn't been committed under share/colldef yet, so that will
provide the first observable change when it happens. Other versioning
schemes are possible in future, because the format is unspecified.

Reviewed by: bapt, 0mp, kib, yuripv (albeit a long time ago)
Differential Revision: https://reviews.freebsd.org/D17166

Allow bootstrapping localdef on non-FreeBSD systems

The current localedef simply assumes that the locale headers on build system
are compatible with those on the target system which is not necessarily true.
It generally works on FreeBSD (as long as we don't change the locale headers),
but Linux and macOS provide completely different locale headers.

This change adds new bootstrap headers that namespace certain xlocale
structures defined or used by in the headers that localdef needs.
This is required since system headers *must* be able to include the "real"
locale headers for printf(), etc., but we also want to access the target
systems's internal locale structures.

Reviewed By: yuripv, brooks
Differential Revision: https://reviews.freebsd.org/D25229