lib/msun: Cleanup after $FreeBSD$ removal

Remove no longer needed explicit inclusion of sys/cdefs.h.

PR: 276669
MFC after: 1 week

Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

Implementations of cexpl()

The change implements cexpl() for both ld80 and ld128 architectures.
Testing was done on x86_64 and aarch64 systems.

Along the way sincos[fl]() use an optimization that reduces the argument
to being done one rather than twice. This optimization actually pointed
to a bug in the ld128 version of sincosl(), which is now fixed. In
addition, the minmax polynomial coefficients for sincosl() have been
updated.

A concise log of the file-by-file changes follows.

* include/complex.h:
. Add a prototype for cexpl().

* lib/msun/Makefile:
. Add s_cexpl.c to the build.
. Setup a link for cexpl.3 to cexp.3.

* lib/msun/Symbol.map:
. Expose cexpl symbol in libm shared library.

* lib/msun/ld128/s_cexpl.c:
* Implementation of cexpl() for 128-bit long double architectures.
Tested on an aarch64 system.

* lib/msun/ld80/s_cexpl.c:
* Implementation of cexpl() for Intel 80-bit long double.

* lib/msun/man/cexp.3:
. Document cexpl().

* lib/msun/man/complex.3:
. Add a BUGS section about cpow[fl].

* lib/msun/src/s_cexp.c:
. Include float.h for weak references on 53-bit long double targets.
. Use sincos() to reduce argument reduction cost.

* lib/msun/src/s_cexpf.c:
. Use sincosf() to reduce argument reduction cost.

* lib/msun/src/k_sincosl.h:
. Catch up with the new minmax polynomial coefficients for the kernel for
the 128-bit cosl() implementation.
. BUG FIX: *cs was used where *sn should have been. This means that sinl()
was no computed correctly when iy != 0.

* lib/msun/src/s_cosl.c:
. Include fpmath.h to get access to IEEEl2bits.
. Replace M_PI_4 with pio4, a 64-bit or 113-bit approximation for pi / 4.

PR: 216862
MFC after: 1 week

lib: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

* Use ENTERI() and RETURNI() to toggle the rounding precision if
necessary, so that cosl(), sinl() and tanl() work on i386 even
for naive callers.

Suggested by: bde
Reviewed by: bde
Approved by: das (mentor)

Clean up the unneeded cpp macro INLINE_REM_PIO2L.

Reviewed by: das
Approved by: das (mentor)

Improve the accuracy from a max ULP of ~2000 to max ULP < 0.79
on i386-class hardware for sinl and cosl. The hand-rolled argument
reduction have been replaced by e_rem_pio2l() implementations. To
preserve history the following commands have been executed:

svn cp src/e_rem_pio2.c ld80/e_rem_pio2l.h
mv ${HOME}/bde/ld80/e_rem_pio2l.c ld80/e_rem_pio2l.h

svn cp src/e_rem_pio2.c ld128/e_rem_pio2l.h
mv ${HOME}/bde/ld128/e_rem_pio2l.c ld128/e_rem_pio2l.h

The ld80 version has been tested by bde, das, and kargl over the
last few years (bde, das) and few months (kargl). An older ld128
version was tested by das. The committed version has only been
compiled tested via 'make universe'.

Approved by: das (mentor)
Obtained from: bde

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

Create the altix project branch. The altix project will add support
for the SGI Altix 350 to FreeBSD/ia64. The hardware used for porting
is a two-module system, consisting of a base compute module and a
CPU expansion module. SGI's NUMAFlex architecture can be an excellent
platform to test CPU affinity and NUMA-aware features in FreeBSD.

- Import the HEAD csup code which is the basis for the cvsmode work.

Add implementations of sinl(), cosl(), and tanl().

Submitted by: Steve Kargl <sgk@apl.washington.edu>