Fix memleak in config parsing (variables weren’t freed)

src/config.c

@@ -280,5 +280,14 @@ void load_configuration(xcb_connection_t *conn, const char *override_configpath)
         REQUIRED_OPTION(terminal);
         REQUIRED_OPTION(font);
 
+
+        while (!SLIST_EMPTY(&variables)) {
+                struct Variable *v = SLIST_FIRST(&variables);
+                SLIST_REMOVE_HEAD(&variables, variables);
+                free(v->key);
+                free(v->value);
+                free(v);
+        }
+ 
         return;
 }