avoid setjmp if we can do it.

C/sysbits.c

@@ -1427,15 +1427,6 @@ InteractSIGINT(int ch) {
     } else {
       Yap_Error(PURE_ABORT, TermNil, "abort from console");
       /* in case someone mangles the P register */
-      save_machine_regs();
-#if  _MSC_VER || defined(__MINGW32__)
-      /* don't even think about trying this */
-#else
-#if PUSH_REGS
-      restore_absmi_regs(&Yap_standard_regs);
-#endif
-      siglongjmp (Yap_RestartEnv, 1);
-#endif
     }
     return -1;
   case 'b':