Explicitly cast TIME_T_MAX to double in tst-timespec.c to silence Clang
error:

tst-timespec.c:290:19: error: implicit conversion from 'time_t' (aka 'long') to 'double' changes value from 9223372036854775807 to 9223372036854775808 [-Werror,-Wimplicit-const-int-float-conversion]
  287 |   {.expected = {.tv_sec = 0, .tv_nsec = 1},
      |   ~
  288 |    .observed = {.tv_sec = TIME_T_MAX / TIMESPEC_HZ,
  289 |                 .tv_nsec = TIMESPEC_HZ - 1},
  290 |    .upper_bound = TIME_T_MAX, .lower_bound = 1, .result = 1,
      |                   ^~~~~~~~~~

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Sam James <sam@gentoo.org>

I used these shell commands:

../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")

and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 7061 files FOO.

I then removed trailing white space from math/tgmath.h,
support/tst-support-open-dev-null-range.c, and
sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following
obscure pre-commit check failure diagnostics from Savannah.  I don't
know why I run into these diagnostics whereas others evidently do not.

remote: *** 912-#endif
remote: *** 913:
remote: *** 914-
remote: *** error: lines with trailing whitespace found
...
remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines

I used these shell commands:

../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")

and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 6694 files FOO.
I then removed trailing white space from benchtests/bench-pthread-locks.c
and iconvdata/tst-iconv-big5-hkscs-to-2ucs4.c, to work around this
diagnostic from Savannah:
remote: *** pre-commit check failed ...
remote: *** error: lines with trailing whitespace found
remote: error: hook declined to update refs/heads/master

commit 04deeaa9ea74b0679dfc9d9155a37b6425f19a9f
Author: Lucas A. M. Magalhaes <lamm@linux.ibm.com>
Date:   Fri Jul 10 19:41:06 2020 -0300

    Fix time/tst-cpuclock1 intermitent failures

has 2 issues:

1. It assumes time_t == long which is false on x32.
2. tst-timespec.c is compiled without -fexcess-precision=standard which
generates incorrect results on i686 in support_timespec_check_in_range:

  double ratio = (double)observed_norm / expected_norm;
  return (lower_bound <= ratio && ratio <= upper_bound);

This patch does

1. Compile tst-timespec.c with -fexcess-precision=standard.
2. Replace long with time_t.
3. Replace LONG_MIN and LONG_MAX with TYPE_MINIMUM (time_t) and
TYPE_MAXIMUM (time_t).

This test fails intermittently in systems with heavy load as
CLOCK_PROCESS_CPUTIME_ID is subject to scheduler pressure.  Thus the
test boundaries were relaxed to keep it from failing on such systems.

A refactor of the spent time checking was made with some support
functions.  With the advantage to representing time jitter in percent
of the target.

The values used by the test boundaries are all empirical.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>