-/* You must include config.h before including this file. */
-
-# include <sys/types.h>
-# if TIME_WITH_SYS_TIME
-# include <sys/time.h>
-# include <time.h>
-# else
-# if HAVE_SYS_TIME_H
-# include <sys/time.h>
-# else
-# include <time.h>
-# endif
-# endif
-
-# if ! HAVE_STRUCT_TIMESPEC
-/* Some systems don't define this struct, e.g., AIX 4.1, Ultrix 4.3. */
-struct timespec
+# include <time.h>
+
+/* Return negative, zero, positive if A < B, A == B, A > B, respectively.
+
+ For each time stamp T, this code assumes that either:
+
+ * T.tv_nsec is in the range 0..999999999; or
+ * T.tv_sec corresponds to a valid leap second on a host that supports
+ leap seconds, and T.tv_nsec is in the range 1000000000..1999999999; or
+ * T.tv_sec is the minimum time_t value and T.tv_nsec is -1; or
+ T.tv_sec is the maximum time_t value and T.tv_nsec is 2000000000.
+ This allows for special struct timespec values that are less or
+ greater than all possible valid time stamps.
+
+ In all these cases, it is safe to subtract two tv_nsec values and
+ convert the result to integer without worrying about overflow on
+ any platform of interest to the GNU project, since all such
+ platforms have 32-bit int or wider.
+
+ Replacing "(int) (a.tv_nsec - b.tv_nsec)" with something like
+ "a.tv_nsec < b.tv_nsec ? -1 : a.tv_nsec > b.tv_nsec" would cause
+ this function to work in some cases where the above assumption is
+ violated, but not in all cases (e.g., a.tv_sec==1, a.tv_nsec==-2,
+ b.tv_sec==0, b.tv_nsec==999999999) and is arguably not worth the
+ extra instructions. Using a subtraction has the advantage of
+ detecting some invalid cases on platforms that detect integer
+ overflow.
+
+ The (int) cast avoids a gcc -Wconversion warning. */
+
+static inline int
+timespec_cmp (struct timespec a, struct timespec b)