role,race,&c options: environment vs config file

Due to the unorthodox values for role, race, gender, and alignment,
specifying a negated value or set of values in NETHACKOPTIONS wasn't
overriding a specific value set in the run-time config file.  The
command line should take priority, then environment, then config file,
lastly builtin defaults.

This could probably use some improvement.  It now treats role:!val
as if there was no val role and the entry was role:random rather than
previous role:none (affects prompting).

[I've just realized that role:!foo in environment will be combined
with role:!bar in config file rather than replacing it.  I'm not sure
how to deal with that.]

doc/fixes3-7-0.txt

@@ -1070,6 +1070,8 @@ throwing recoil while levitating could send hero out of shop while carrying
 	a step other than back into the shop was treated as a robbery
 if punished and iron ball was cursed and wielded--so welded to hand--falling
 	when doors would drop it instead of keeping it welded
+if player's run-time config file had OPTIONS=role:Val and the environment had
+	NETHACKOPTIONS='role:!Val' the hero would be a Val instead of !Val
 
 
 Fixes to 3.7.0-x Problems that Were Exposed Via git Repository

src/options.c

@@ -7477,6 +7477,7 @@ parse_role_opts(
     char *opts,
     char **opp)
 {
+    static char role_random[] = "random"; /* not 'const' but never modified */
     char *op = *opp;
     boolean ok = FALSE;
 
@@ -7535,6 +7536,8 @@ parse_role_opts(
                     complain_about_duplicate(optidx);
                 *opp = op;
                 ok = TRUE;
+                /* don't return yet; value might be a list which follows
+                   this with something else, making it invalid */
             }
 
             if (sp) {
@@ -7544,6 +7547,15 @@ parse_role_opts(
                 op += strlen(op); /* break; */
             }
         }
+
+        if (!ok) {
+            /* '!ok' without config_error_add() implies a valid negation;
+               in case NETHACKOPTIONS=role:!Val overrides config file
+               OPTIONS=role:Val we need a positive result which will yield
+               someting other than ROLE_NONE from str2role(),str2race(),&c */
+            *opp = role_random;
+            ok = TRUE;
+        }
     }
     return ok;
 }