msvcrt: Use NULL instead of casting zero.

dlls/msvcrt/tests/scanf.c

@@ -51,7 +51,7 @@ static void test_sscanf( void )
     ok( ptr == (void *)0x46F172,"sscanf reads %p instead of %x\n", ptr, 0x46F172 );
 
     ok( sscanf("0x46F173", "%p", &ptr) == 1, "sscanf failed\n"  );
-    ok( ptr == (void *)0,"sscanf reads %p instead of %x\n", ptr, 0 );
+    ok( ptr == NULL,"sscanf reads %p instead of %x\n", ptr, 0 );
 
     ok( sscanf("-46F174", "%p", &ptr) == 1, "sscanf failed\n"  );
     ok( ptr == (void *)0xFFB90E8C,"sscanf reads %p instead of %x\n", ptr, 0xFFB90E8C );

dlls/msvcrt/time.c

@@ -340,7 +340,7 @@ void CDECL MSVCRT__tzset(void)
         struct tm *tmp;
         long zone_january, zone_july;
 
-        t = (time((time_t *)0) / seconds_in_year) * seconds_in_year;
+        t = (time(NULL) / seconds_in_year) * seconds_in_year;
         tmp = localtime(&t);
         zone_january = -tmp->tm_gmtoff;
         t += seconds_in_year / 2;