hangman(6): skip retguard symbols

[Theo Buehler]

__retguard_NNNN symbols are easy to recognize and no real fun to guess.
I suggest we skip them. Perhaps we should even skip all __* symbols?

Index: ksyms.c
===================================================================
RCS file: /cvs/src/games/hangman/ksyms.c,v
retrieving revision 1.12
diff -u -p -r1.12 ksyms.c
--- ksyms.c     28 Jun 2019 13:32:52 -0000      1.12
+++ ksyms.c     23 Dec 2021 18:28:02 -0000
@@ -70,6 +70,9 @@ sym_getword(void)
                /* ignore symbols containing dots or dollar signs */
                if (strchr(sym, '.') != NULL || strchr(sym, '$') != NULL)
                        continue;
+               /* guessing retguard symbols is no fun */
+               if (strncmp(sym, "__retguard", 10) == 0)
+                       continue;
 
                break;
        }