lib: don't assume time_t is signed.

We introduce the function c_time to convert a Lisp integer
to time_t, and num_time to do the reverse conversion.
The FFI type time-t already does this right.
(See registration of time-t in ffi_init_extra_types).

* hash.c (gen_hash_seed): The first value out of time_sec_usec
corresponds to a time_t value. We now convert this to C number
using c_time rather than c_num. Also, while we are touching
this code, the microseconds value can convert directly to
ucnum with c_unum.

* lib.c (time_sec_usec): Use num_time for seconds.
(time_string_local, time_string_utc, time_fields_local,
time_fields_utc, time_struct_local, time_struct_utc): Use c_time.
(make_time_impl, time_parse_utc): Use num_time instead of num.

* signal.h (getitimer_wrap, setitimer_wrap): Convert tv_sec
members of struct timeval using c_time and num_time.

* sysif.c (c_time, num_time): New functions.
(stat_to_struct): Convert st_atime, st_mtime and st_ctime
to Lisp using num_time instead of num.

* sysif.c (c_time, num_time): Declared.

1 files changed, 3 insertions, 2 deletions

diff --git a/hash.c b/hash.c
index 20c869bf..bde7901f 100644
--- a/hash.c
+++ b/hash.c
@@ -46,6 +46,7 @@
 #include "eval.h"
 #include "itypes.h"
 #include "arith.h"
+#include "sysif.h"
 #include "hash.h"
 
 typedef enum hash_flags {
@@ -1818,8 +1819,8 @@ static val set_hash_traversal_limit(val lim)
 static val gen_hash_seed(void)
 {
     val time = time_sec_usec();
-    ucnum sec = convert(ucnum, c_num(car(time)));
-    ucnum usec = convert(ucnum, c_num(cdr(time)));
+    ucnum sec = convert(ucnum, c_time(car(time)));
+    ucnum usec = c_unum(cdr(time));
 #if HAVE_UNISTD_H
     ucnum pid = convert(ucnum, getpid());
 #else