* lib/readutmp.c (get_boot_time_uncached, get_boot_time)
(add_utmp, read_utmp):
Use struct timespec, not struct timeval.
* lib/readutmp.h: Always include <time.h>, for struct timespec.
Simplify when utmp.h and utmpx.h are included.
(struct gl_utmp): Use the same struct for both the
systemd and the dummy version. Reorder members, and
use proper pid_t type for ut_session. Rename ut_tv to ut_ts
and make it a struct timespec. All uses changed.
(HAVE_GL_UTMP): New macro. Use it where appropriate, instead
of READUTMP_USE_SYSTEMD.
(UT_USER, HAVE_STRUCT_XTMP_UT_EXIT, HAVE_STRUCT_XTMP_UT_ID)
(HAVE_STRUCT_XTMP_UT_PID, HAVE_STRUCT_XTMP_UT_HOST):
Simplify.
* modules/readutmp (Depends-on): Add time-h, timespec_get.
Remove sys_type. Sort.