STR 2348: fixed possibly wrong relative path

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@7778 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

CHANGES

@@ -1,5 +1,6 @@
 CHANGES IN FLTK 1.3.0
 
+	- Fixed wrong relative path (STR #2384)
 	- Fixed static allocation in Fl_Tabs (STR #2370)
 	- Fixed Fl_Widget::measure_label() to const (STR #2406)
 	- Added step by step README's for MSWindows, OS X, and four

src/filename_absolute.cxx

@@ -210,6 +210,7 @@ fl_filename_relative(char       *to,	// O - Relative filename
   if (isdirsep(*slash)) slash ++;
 
   // do the same for the current dir
+  if (isdirsep(*newslash)) newslash --;
   if (*newslash != '\0')
     while (!isdirsep(*newslash) && newslash > cwd) newslash --;