lib: Automated cleanup of cdefs and other formatting

Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.

Remove /^#if.*\n#endif.*\n#include\s+<sys/cdefs.h>.*\n/
Remove /\n+#include\s+<sys/cdefs.h>.*\n+#if.*\n#endif.*\n+/
Remove /\n+#if.*\n#endif.*\n+/
Remove /^#if.*\n#endif.*\n/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/types.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/param.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/capsicum.h>/

Sponsored by: Netflix

Remove $FreeBSD$: one-line .c pattern

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

msun: Remove a double word in a source code comment

- s/the the/the/

MFC after: 3 days

lib/msun/tests: Add more debug output to fenv_test.c

Output a hex dump of the current fenv and the expected value to allow
comparing them without having to resort to interactive use of GDB.

lib/msun/tests: Skip fenv_test:masking if exceptions can't be trapped

Some CPUs (e.g. AArch64 QEMU) cannot trap on floating point exceptions and
therefore ignore the writes to the floating point control register inside
feenableexcept(). If no exceptions are enabled after
feenableexcept(FE_ALL_EXCEPT), we can assume that the CPU does not
support exceptions and we can then skip the test.

Reviewed By: dim
Differential Revision: https://reviews.freebsd.org/D29095

Improve test messages for msun tests

Also print the mismatched values when numbers compare not equal.

Reviewed By: dim
Differential Revision: https://reviews.freebsd.org/D29091

Convert the msun tests to ATF

This provides better error messages that just an assertion failure and
also makes it easier to mark individual tests as XFAIL.
It was also helpful when coming up with D28786 and D28787.

Differential Revision: https://reviews.freebsd.org/D28798

Avoid double output in fenv_test

This tests fork()s, so if there is still data in the stdout buffer on fork
it will print it again in the child process. This was happening in the
CheriBSD CI and caused the test to complain about malformed TAP output.

Reviewed By: ngie
Differential Revision: https://reviews.freebsd.org/D28397

msun tests: use standard floating-point exception flags on lrint and fenv tests

Some platforms have additional architecture-specific floating-point flags.
Msun test cases lrint and test_fegsetenv (fenv) expects only standard flags,
so make sure to mask them appropriately.

This makes test pass on PowerPC64.

Reviewed by: jhibbits, ngie
Sponsored by: Eldorado Research Institute (eldorado.org.br)
Differential Revision: https://reviews.freebsd.org/D27202

Fix warnings in lib/msun/tests/... to help pave way for WARNS?= 6.

- Staticize variables.
- Use nitems liberally. Wherever nitems is used, use unsigned integers
- Remove unused variables (argc, argv, etc)

This fixes most issues -- some issues remain in logarithm_test though.

MFC after: 1 week
Sponsored by: Dell EMC Isilon

Integrate a number of testcases from tools/regression/lib/msun
into the FreeBSD test suite

There's no functional change with these testcases; they're purposely
being left in TAP format for the time being

Other testcases which crash on amd64/i386 as-is have not been
integrated yet (they need to be retested on a later version of
CURRENT, as I haven't used i386 in some time)

MFC after: 3 weeks
Sponsored by: EMC / Isilon Storage Division