define ROKEN_LIB_FUNCTION on all exported functions

git-svn-id: svn://svn.h5l.se/heimdal/trunk/heimdal@14773 ec53bebd-3082-4978-b11e-865c3cabbd6b

lib/roken/get_default_username.c

@@ -43,7 +43,7 @@ RCSID("$Id$");
  * NULL if we can't guess at all.
  */
 
-const char *
+const char * ROKEN_LIB_FUNCTION
 get_default_username (void)
 {
     const char *user;