SCP: Fold up include files used by all simulators

- Add common system includes used in may places which are allowed
  and thus added directly in sim_defs.h.
- Separate completely private system data structures and system APIs
  for use only by SCP library routines into sim_scp_private.h.

sim_card.c

@@ -76,7 +76,6 @@
 */
 
 
-#include <ctype.h>
 #include "sim_defs.h"
 #include "sim_card.h"
 
@@ -1468,8 +1467,6 @@ fclose (f);
 return SCPE_OK;
 }
 
-#include <setjmp.h>
-
 t_stat sim_card_test (DEVICE *dptr, const char *cptr)
 {
 t_stat stat = SCPE_OK;