merge r14123 from cpstrnew branch by paul:

fix string ref count for empty strings

git-svn-id: trunk@19089 -

rtl/inc/astrings.inc

@@ -1141,7 +1141,7 @@ function StringRefCount(const S: RawByteString): SizeInt; overload;
     if assigned(Pointer(S)) then
       Result:=PAnsiRec(pointer(S)-AnsiFirstOff)^.Ref
     else
-      Result:=SizeOf(AnsiChar);
+      Result:=0;
   end;
 
 

rtl/inc/ustrings.inc

@@ -2564,7 +2564,7 @@ function StringRefCount(const S: UnicodeString): SizeInt; overload;
     if assigned(Pointer(S)) then
       Result:=PUnicodeRec(pointer(S)-UnicodeFirstOff)^.Ref
     else
-      Result:=SizeOf(UnicodeChar);
+      Result:=0;
   end;