Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC the xlocale implementation.

Merged revisions: 227487,227753,227807,227818,227999,228002,228875,230156,231673,232498,232601,232620,232626,232926-232927,232929,232931,232935,233173,233600,234573,234578,235239

This currently defines __NO_TLS on ARM (unlike head), because the required
support function has not been MFC'd.

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Add wcpcpy(3) and wcpncpy(3).

- Add getdelim(), getline(), stpncpy(), strnlen(), wcsnlen(),
wcscasecmp(), and wcsncasecmp().
- Make some previously non-standard extensions visible
if POSIX_VISIBLE >= 200809.
- Use restrict qualifiers in stpcpy().
- Declare off_t and size_t in stdio.h.
- Bump __FreeBSD_version in case the new symbols (particularly
getline()) cause issues with ports.

Reviewed by: standards@

Import the strndup(3) function.
Copyright attribution is kept the same as in original NetBSD source.

Submitted by: Florian Smeets <flo kasimir com>
Obtained from: NetBSD
MFC after: 2 weeks

Add the ffsll and flsll functions. These are ffs and fls operating
on long long arguments.

Reviewed by: bde (previous version, that included asm implementation
for all ffs and fls functions on i386 and amd64)
MFC after: 2 weeks

Add memrchr(3).

Obtained from: OpenBSD

Use C comments since we now preprocess these files with CPP.

Add symbol maps and initial symbol version definitions to libc.

Reviewed by: davidxu