remove redundant feature test macro checks in sys/time.h

this header is XSI-shaded itself and thus does not need to limit
specific content to _XOPEN_SOURCE.

include/sys/time.h

@@ -10,9 +10,6 @@ extern "C" {
 
 int gettimeofday (struct timeval *__restrict, void *__restrict);
 
-#if defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE) \
- || defined(_BSD_SOURCE)
-
 #define ITIMER_REAL    0
 #define ITIMER_VIRTUAL 1
 #define ITIMER_PROF    2
@@ -26,8 +23,6 @@ int getitimer (int, struct itimerval *);
 int setitimer (int, const struct itimerval *__restrict, struct itimerval *__restrict);
 int utimes (const char *, const struct timeval [2]);
 
-#endif
-
 #if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
 struct timezone {
 	int tz_minuteswest;