SCP: Add GOTO :EOF as a means of returning from a DO command

scp.c

@@ -1755,6 +1755,10 @@ static const char simh_help[] =
       " in the current do command file which is encountered.  Since labels\n"
       " don't do anything else besides being the targets of goto's, they could\n"
       " also be used to provide comments in do command files.\n\n"
+      "++GOTO :EOF\n\n"
+      " The target label of :EOF is explicitly defined to mean the end of the\n"
+      " DO command file.  This will cause the execution to return from the current\n"
+      " command file.\n\n"
       "4Examples\n\n"
       "++:: This is a comment\n"
       "++echo Some Message to Output\n"
@@ -5049,6 +5053,13 @@ if ('\0' == gbuf1[0])                                   /* unspecified goto targ
 fpos = ftell(sim_gotofile);                             /* Save start position */
 if (fpos < 0)
     return sim_messagef (SCPE_IERR, "goto ftell error: %s\n", strerror (errno));
+if (strcasecmp(":EOF", gbuf1) == 0) {
+    if (fseek (sim_gotofile, 0, SEEK_END))
+        return sim_messagef (SCPE_IERR, "goto seek error: %s\n", strerror (errno));
+    sim_brk_clract ();                                  /* goto defangs current actions */
+    sim_do_echo = saved_do_echo;                        /* restore echo mode */
+    return SCPE_OK;
+    }
 rewind(sim_gotofile);                                   /* start search for label */
 sim_goto_line[sim_do_depth] = 0;                        /* reset line number */
 sim_do_echo = 0;                                        /* Don't echo while searching for label */