These features are available in all supported linkers, and we can expect
that they'll be supported by any GNU-compatible linker that we'd use to
link FreeBSD.

Reviewed by:	imp, kib
Sponsored by:	The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D55676

NO_FP_LIBC was added in 2004 to save space by disabling FP support in
*printf()/*scanf(). The size benefit is negligible on modern systems
and conflicts with assumptions made by current base utilities.

Remove the option and always build libc with floating-point support.

Reported by:	Oskar Holmlund <eovholmlund at gmail com>
MFC after:	2 weeks

This new header complies with ISO/IEC 9899:2024 (C23).

Contrary to glibc, we do not provide inline definitions in
<stdbit.h> as we expect our system compiler to soon recognise
these as builtins anyway.

Relnotes:	yes
MFC after:	1 month
Reviewed by:	adrian
Approved by:	markj (mentor)
Differential Revision:	https://reviews.freebsd.org/D53657

MD5 is used by libc/resolv to generate a random sequence id from a
current time stamp.  Replace this convoluted mechanism with a call
to arc4random().  This permits us to entirely drop MD5 from libc,
simplifying the MD5 rework proposed in D45670.

Approved by:	markj
Reviewed by:	kevans, markj
See also:	D45670
Event:		EuroBSDcon 2025
Differential Revision:	https://reviews.freebsd.org/D52784

Reduce the number of md5c.c between the three of these from two to one
by just reaching into the kernel build for both userland builds.  The
precedent for this already exists for sha2 in both cases.

_libmd_ symbol privatization bits have been moved to sys/md5.h and
md5.h remains to #include <sys/md5.h> for compatibility.

This stops exporting MD5Pad() in the process because the kernel stopped
exporting it in 502a35d60f4c.  soversion is bumped accordingly.

This also renames the libc version of stack_protector.c; it previously
only worked by coincidence because .PATH ordering worked out such that
we got the right one, but this is not the case anymore.  Remove the
landmine.

PR:		280784 (exp-run)
Reviewed by:	allanjude, delphij
Differential Revision:	https://reviews.freebsd.org/D34497

This is a residual of the $FreeBSD$ removal.

MFC After: 3 days (though I'll just run the command on the branches)
Sponsored by: Netflix

Notably:
- libc needs to #undef some of the macros from ssp/* for underlying
  implementations
- ssp/* wants a __RENAME() macro (snatched more or less from NetBSD)

There's some extra hinkiness included for read(), since libc spells it
as "_read" while the rest of the world spells it "read."

Reviewed by:	imp, ngie
Sponsored by:	Stormshield
Sponsored by:	Klara, Inc.
Differential Revision:	https://reviews.freebsd.org/D32307

These provide standard APIs, but are implemented using another system
call (e.g., pipe implemented in terms of pipe2) or are interposed by the
threading library to support cancelation.

After discussion with kib (see D44111), I've concluded that it is
better to keep most public interfaces in libc with as little
as possible in libsys.

Reviewed by:	kib
Differential Revision:	https://reviews.freebsd.org/D44241

To allow gcc -m32 to work, link libc and libthr with --rpath-/usr/lib32.
When called with -m32, gcc is currently unable to communicate to
the bfd linker that it should look in /usr/lib32 to resolve needed (as
opposed to explicitly linked) libraries so we need to provide a hint.

See also: https://sourceware.org/bugzilla/show_bug.cgi?id=31395

Reviewed by:	kib
Differential Revision:	https://reviews.freebsd.org/D43910

Continue to filter the public interface (elf_aux_info()), but entierly
relocate the private interfaces (_elf_aux_info(),
__init_elf_aux_vector(), and __elf_aux_vector) to libsys.

This ensures that rtld updates the correct (only) copy of
__elf_aux_vector.  After 968a18975adc9c2a619bb52aa2f009de99fc9e24
updates were confused and __getosreldate was failing, causing
the system to fall back to compat compat12 syscalls in some cases.

Return to explicitly linking libc to libsys and link libthr with libc
and libsys (in that order).

Reviewed by:	kib
Differential Revision:	https://reviews.freebsd.org/D43910