various: timespec/timeval.tv_sec is time_t, not long, according to POSIX

This matters on 32 bit systems configured with 64 bit time_t
(so they survive beyond 2038). Casting them to long is causing loss of bits
and badly mismatched time data.

Author: kanavin

dist/threads-shared/shared.xs

@@ -697,7 +697,7 @@ Perl_sharedsv_cond_timedwait(perl_cond *cond, perl_mutex *mut, double abs)
     struct timespec ts;
     int got_it = 0;
 
-    ts.tv_sec = (long)abs;
+    ts.tv_sec = (time_t)abs;
     abs -= (NV)ts.tv_sec;
     ts.tv_nsec = (long)(abs * 1000000000.0);
 

doio.c

@@ -2874,9 +2874,9 @@ nothing in the core.
            else {
                 Zero(&utbuf, sizeof utbuf, char);
 #ifdef HAS_FUTIMES
-                utbuf[0].tv_sec = (long)SvIV(accessed);  /* time accessed */
+                utbuf[0].tv_sec = (time_t)SvIV(accessed);  /* time accessed */
                 utbuf[0].tv_usec = 0;
-                utbuf[1].tv_sec = (long)SvIV(modified);  /* time modified */
+                utbuf[1].tv_sec = (time_t)SvIV(modified);  /* time modified */
                 utbuf[1].tv_usec = 0;
 #elif defined(BIG_TIME)
                 utbuf.actime = (Time_t)SvNV(accessed);  /* time accessed */

pp_sys.c

@@ -1228,7 +1228,7 @@ PP(pp_sselect)
         value = SvNV_nomg(sv);
         if (value < 0.0)
             value = 0.0;
-        timebuf.tv_sec = (long)value;
+        timebuf.tv_sec = (time_t)value;
         value -= (NV)timebuf.tv_sec;
         timebuf.tv_usec = (long)(value * 1000000.0);
     }