Show charsets dir in error message, instead of just "path: default".

include/my_sys.h:
  make get_charsets_dir a public function
libmysql/libmysql.c:
  show charsets dir instead of the string "default" in error message
mysys/charset.c:
  make get_charsets_dir a public function

include/my_sys.h

@@ -178,6 +178,7 @@ extern CHARSET_INFO *get_charset_by_name(const char *cs_name, myf flags);
 extern my_bool set_default_charset_by_name(const char *cs_name, myf flags);
 extern void free_charsets(void);
 extern char *list_charsets(myf want_flags); /* my_free() this string... */
+extern char *get_charsets_dir(char *buf);
 
 
 /* statistics */

libmysql/libmysql.c

@@ -1394,10 +1394,18 @@ mysql_real_connect(MYSQL *mysql,const char *host, const char *user,
   if (!mysql->charset)
   {
     net->last_errno=CR_CANT_READ_CHARSET;
-    sprintf(net->last_error,ER(net->last_errno),
-	    charset_name ? charset_name : "unknown",
-	    mysql->options.charset_dir ? mysql->options.charset_dir :
-	    "default");
+    if (mysql->options.charset_dir)
+      sprintf(net->last_error,ER(net->last_errno),
+              charset_name ? charset_name : "unknown",
+              mysql->options.charset_dir);
+    else
+    {
+      char cs_dir_name[FN_REFLEN];
+      get_charsets_dir(cs_dir_name);
+      sprintf(net->last_error,ER(net->last_errno),
+              charset_name ? charset_name : "unknown",
+              cs_dir_name);
+    }
     goto error;
   }
 

mysys/charset.c

@@ -94,7 +94,7 @@ static my_bool get_word(struct simpleconfig_buf_st *fb, char *buf)
 }
 
 
-static char *get_charsets_dir(char *buf)
+char *get_charsets_dir(char *buf)
 {
   const char *sharedir = SHAREDIR;
   DBUG_ENTER("get_charsets_dir");