Don't use the argument to time.

It doesn't make sense to remove all the internal uses of time.
It's still a standard ISO C function, and its callers don't need
sub-second resolution and would be unnecessarily complicated if
they had to declare a struct timespec instead of just a time_t.
However, a handful of places were using the vestigial "result"
argument instead of the return value, which is slightly less
efficient and also looks strange.  Correct this.

	* misc/syslog.c (__vsyslog_internal)
	* time/getdate.c (__getdate_r)
	* time/tst_wcsftime.c (main):
	Use return value of time, not its argument.

	* string/strfry.c (strfry)
	* sysdeps/mach/sleep.c (__sleep):
	Remove unnecessary casts of NULL in calls to time.

ChangeLog

@@ -1,3 +1,14 @@
+2019-08-21  Zack Weinberg  <zackw@panix.com>
+
+	* misc/syslog.c (__vsyslog_internal)
+	* time/getdate.c (__getdate_r)
+	* time/tst_wcsftime.c (main):
+	Use return value of time, not its argument.
+
+	* string/strfry.c (strfry)
+	* sysdeps/mach/sleep.c (__sleep):
+	Remove unnecessary casts of NULL in calls to time.
+
 2019-08-21  Joseph Myers  <joseph@codesourcery.com>
 
 	* math/tgmath.h [__HAVE_FLOAT128X]: Give error.

misc/syslog.c

@@ -205,7 +205,7 @@ __vsyslog_internal(int pri, const char *fmt, va_list ap,
 	  {
 	    __fsetlocking (f, FSETLOCKING_BYCALLER);
 	    fprintf (f, "<%d>", pri);
-	    (void) time (&now);
+	    now = time (NULL);
 	    f->_IO_write_ptr += __strftime_l (f->_IO_write_ptr,
 					      f->_IO_write_end
 					      - f->_IO_write_ptr,

string/strfry.c

@@ -30,7 +30,7 @@ strfry (char *string)
     {
       static char state[32];
       rdata.state = NULL;
-      __initstate_r (time ((time_t *) NULL) ^ getpid (),
+      __initstate_r (time (NULL) ^ getpid (),
 		     state, sizeof (state), &rdata);
       init = 1;
     }

sysdeps/mach/sleep.c

@@ -33,10 +33,10 @@ __sleep (unsigned int seconds)
 
   recv = __mach_reply_port ();
 
-  before = time ((time_t *) NULL);
+  before = time (NULL);
   (void) __mach_msg (NULL, MACH_RCV_MSG|MACH_RCV_TIMEOUT|MACH_RCV_INTERRUPT,
 		     0, 0, recv, seconds * 1000, MACH_PORT_NULL);
-  after = time ((time_t *) NULL);
+  after = time (NULL);
   __mach_port_destroy (__mach_task_self (), recv);
 
   return seconds - (after - before);

time/getdate.c

@@ -219,7 +219,7 @@ __getdate_r (const char *string, struct tm *tp)
     return 7;
 
   /* Get current time.  */
-  time (&timer);
+  timer = time (NULL);
   __localtime_r (&timer, &tm);
 
   /* If only the weekday is given, today is assumed if the given day

time/tst_wcsftime.c

@@ -10,7 +10,7 @@ main (int argc, char *argv[])
   int result = 0;
   size_t n;
 
-  time (&t);
+  t = time (NULL);
   tp = gmtime (&t);
 
   n = wcsftime (buf, sizeof (buf) / sizeof (buf[0]),