Switch to a 64-bit time_t everywhere except 32-bit x86.

Thus, BeOS compatibility is preserved (and there is no risk of
breaking GCC5<->GCC2 interoperation on hybrid builds.)

This commit only makes the actual change, the build fixes are
in the next commit.

headers/posix/time.h

@@ -13,10 +13,15 @@ struct sigevent;	/* defined in <signal.h> */
 
 
 typedef __haiku_int32 clock_t;
-typedef __haiku_int32 time_t;
 typedef __haiku_int32 suseconds_t;
 typedef __haiku_uint32 useconds_t;
 
+#if defined(__i386__) && !defined(__x86_64__)
+typedef __haiku_int32 time_t;
+#else
+typedef __haiku_int64 time_t;
+#endif
+
 
 #define CLOCKS_PER_SEC	1000000
 #define CLK_TCK			CLOCKS_PER_SEC