SCP: Add global variable with the program name

Included from Dave Bryan's V3.11 extensions

scp.c

@@ -563,6 +563,7 @@ static t_stat _sim_debug_flush (void);
 
 /* Global data */
 
+const char *sim_prog_name = NULL;                       /* pointer to the executable name */
 DEVICE *sim_dflt_dev = NULL;
 UNIT *sim_clock_queue = QUEUE_LIST_END;
 int32 sim_interval = 0;
@@ -2546,6 +2547,7 @@ set_prompt (0, "sim>");                                 /* start with set standa
 sim_switches = 0;                                       /* init switches */
 lookswitch = TRUE;
 stdnul = fopen(NULL_DEVICE,"wb");
+sim_prog_name = argv [0];                               /* save a pointer to the program name */
 for (i = 1; i < argc; i++) {                            /* loop thru args */
     if (argv[i] == NULL)                                /* paranoia */
         continue;

scp.h

@@ -389,6 +389,7 @@ extern uint32 sim_brk_summ;
 extern uint32 sim_brk_match_type;
 extern t_addr sim_brk_match_addr;
 extern BRKTYPTAB *sim_brk_type_desc;                    /* type descriptions */
+extern const char *sim_prog_name;                       /* executable program name */
 extern FILE *stdnul;
 extern t_bool sim_asynch_enabled;
 #if defined(SIM_ASYNCH_IO)