CLEANUP: time: refine the test on _POSIX_TIMERS
The clock_gettime() man page says we must check that _POSIX_TIMERS is
defined to a value greater than zero, not just that it's simply defined
so let's fix this right now.
diff --git a/include/common/compat.h b/include/common/compat.h
index d43b89d..35782de 100644
--- a/include/common/compat.h
+++ b/include/common/compat.h
@@ -99,7 +99,7 @@
#endif
/* systems without such defines do not know clockid_t */
-#if !defined(_POSIX_TIMERS) || (_POSIX_C_SOURCE < 199309L)
+#if !(_POSIX_TIMERS > 0) || (_POSIX_C_SOURCE < 199309L)
#define clockid_t int
#undef CLOCK_REALTIME
#undef CLOCK_MONOTONIC