Don't assume time_t can fit into int.

* buffer.h (struct buffer.modtime): Now time_t, not int.
* fileio.c (Fvisited_file_modtime): No need for time_t cast now.
* undo.c (Fprimitive_undo): Use time_t, not int, for time_t value.

diff --cc src/ChangeLog
index 05d0baa3ac5a7a307b89b7f2b639ac97ba2ffb36,94cfd944adc055def0c922696a954eafa376ad5b..9f54dcc3bc59a494cb8a3102df9343607e4d82e0
--- 1/src/ChangeLog
--- 2/src/ChangeLog
+++ b/src/ChangeLog
@@@ -1,5 -1,10 +1,10 @@@
 -2011-06-03  Paul Eggert  <eggert@cs.ucla.edu>
 +2011-06-06  Paul Eggert  <eggert@cs.ucla.edu>
  
+       Don't assume time_t can fit into int.
+       * buffer.h (struct buffer.modtime): Now time_t, not int.
+       * fileio.c (Fvisited_file_modtime): No need for time_t cast now.
+       * undo.c (Fprimitive_undo): Use time_t, not int, for time_t value.
+ 
        Minor fixes for signed vs unsigned integers.
        * character.h (MAYBE_UNIFY_CHAR):
        * charset.c (maybe_unify_char):