Use the implementation of time() from the common libc, since there
it no longer pulls in POSIX.

Use is implied for minimal, newlib, and picolibc, and selected
for IAR.

Signed-off-by: Chris Friedt <[email protected]>

Reduce the dependency on POSIX by taking advantage of the newly added
sys_clock_nanosleep().

Signed-off-by: Chris Friedt <[email protected]>

The C standard does not guarantee that `thrd_success` is equal to
zero, so ensure that the test takes that into account.

Signed-off-by: Chris Friedt <[email protected]>

The specification does not say that the first struct timespec passed to
thrd_sleep() may be NULL.

Preserving the testpoint so that a possible future testsuite can be
run that expects faults to occur when undefined behaviour is used.

Faults are one possible solution to handling undefined behaviour, but
it would be good to come to a concensus about how that should be
handled in Zephyr for standard function calls belonging to ISO C or
POSIX.

Signed-off-by: Chris Friedt <[email protected]>

Use `timespec_from_timeout(K_MSEC(msec), &ts)` instead of leaning on
lazily-crafted timespecs with invalid tv_nsec fields.

Signed-off-by: Chris Friedt <[email protected]>

Use sys_clock_gettime() instead of clock_gettime() and use
timespec_add() instead of manually adding timespec structures.

Signed-off-by: Chris Friedt <[email protected]>

Presumably the time testsuite was separate from the c library set of
testsuites because it had a depedency on POSIX.

Since that dependency no longer exists, colocate the time testsuite
with the other c library testsuites.

Signed-off-by: Chris Friedt <[email protected]>

Use the newly added sys_clock API in lib/os for

* clock_gettime()
* clock_settime()
* clock_nanosleep() and nanosleep()
* gettimeofday()

Signed-off-by: Chris Friedt <[email protected]>

The ISO C function time() should not depend on POSIX and this was
corrected recently via the common libc time() implementation.

Remove this dependency from the network subsystem where it has
been unduly needed for some time.

Similarly, XSI_SINGLE_PROCESS was a dependency for time() via
picolibc, because the time() implementation in picolibc relies
on the POSIX gettimeofday() call.

However, since Zephyr's common libc time() implementation no longer
depends on that, it can be removed as a dependency in the network
subsystem as well.

Signed-off-by: Chris Friedt <[email protected]>

Remove POSIX_TIMERS and XSI_SINGLE_PROCESS dependencies from the aws
cloud sample and the lwm2m client sample, as they are no longer
required.

Signed-off-by: Chris Friedt <[email protected]>

Merge sys_clock.h into sys/clock.h and preserve the original header.

This allows us to use a slightly more intuitive name for the
sys/clock.h header, while reducing churn throughout the codebase.

Signed-off-by: Chris Friedt <[email protected]>