Allow optional parameter for boolean config options

Some people try to set boolean options in the config file
by giving the option a parameter, so allow that:

OPTIONS=color:true

Allowed parameters are "true", "yes", "false", and "no".
Negating an option and giving it a parameter is an error.

doc/fixes36.1

@@ -55,6 +55,7 @@ make travel walk up to a trap and stop when the trap blocks the only
 travel will displace pets rather than stop
 do not autopickup unpaid items in shops
 death due an unseen gas spore's explosion resulted in "killed by a died"
+allow optional parameter "true", "yes", "false", or "no" for boolean options
 
 
 Platform- and/or Interface-Specific Fixes

src/options.c

@@ -3298,7 +3298,7 @@ boolean tinitial, tfrom_file;
      * options list
      */
     for (i = 0; boolopt[i].name; i++) {
-        if (match_optname(opts, boolopt[i].name, 3, FALSE)) {
+        if (match_optname(opts, boolopt[i].name, 3, TRUE)) {
             /* options that don't exist */
             if (!boolopt[i].addr) {
                 if (!initial && !negated)
@@ -3312,6 +3312,23 @@ boolean tinitial, tfrom_file;
                 return;
             }
 
+            op = string_for_opt(opts, TRUE);
+
+            if (op) {
+                if (negated) {
+                    badoption(opts);
+                    return;
+                }
+                if (!strcmp(op, "true") || !strcmp(op, "yes"))
+                    negated = FALSE;
+                else if (!strcmp(op, "false") || !strcmp(op, "no"))
+                    negated = TRUE;
+                else {
+                    badoption(opts);
+                    return;
+                }
+            }
+
             *(boolopt[i].addr) = !negated;
 
             /* 0 means boolean opts */