Factor int-properties macros into a single file, except for

Factor int-properties macros into a single file, except for
glibc-related files.
* lib/intprops.h: New file.
* lib/getloadavg.c: Include it instead of limits.h.
(INT_STRLEN_BOUND): Remove.
* lib/human.c: Include intprops.h.
(group_number): Use INT_STRLEN_BOUND instead of rolling it ourself.
* lib/human.h (LONGEST_HUMAN_READABLE): Use 146/485 rather than 302/1000.
* lib/inttostr.h: Include intprops.h instead of limits.h.
(INT_STRLEN_BOUND, INT_BUFSIZE_BOUND): Remove.
* lib/mktime.c (TYPE_IS_INTEGER, TYPE_TWOS_COMPLEMENT): New macros,
for consistency with intprops.h.
(time_t_is_integer, twos_complement_arithmetic): Use them.
* lib/sig2str.h: Include <signal.h>, intprops.h.
(INT_STRLEN_BOUND): Remove.
* lib/strftime.c (TYPE_SIGNED): Remove.
(INT_STRLEN_BOUND): Switch to same implementation as intprops.h.
* lib/strtol.c: Adjust comments to match intprops.h.
* lib/userspec.c: Include intprops.h.
(TYPE_SIGNED, TYPE_MINIMUM, TYPE_MAXIMUM): Remove.
* lib/utimecmp.c, lib/xnanosleep.c, lib/xstrtol.c: Likewise.
* lib/utimecmp.c (utimecmp): Use TYPE_IS_INTEGER, TYPE_TWOS_COMPLEMENT
instead of rolling our own expressions.
* lib/xstrtol.c: Include xstrtol.h first, to test interface.
* modules/getloadavg (Files): Add lib/intprops.h.
* modules/human (Files): Likewise.
* modules/inttostr (Files): Likewise.
* modules/sig2str (Files): Likewise.
* modules/userspec (Files): Likewise.
* modules/utimecmp (Files): Likewise.
* modules/xnanosleep (Files): Likewise.
* modules/xstrtol (Files): Likewise.