rtl: missing FPC_UNICODESTRING_TYPE_DEFINED define

git-svn-id: trunk@23600 -

rtl/inc/ustrings.inc

@@ -18,6 +18,7 @@
 
 
 {$ifndef FPC_UNICODESTRING_TYPE_DEFINED}
+{$define FPC_UNICODESTRING_TYPE_DEFINED}
 {
   This file contains the implementation of the UnicodeString type,
   and all things that are needed for it.