- Hide _rl_qsort_string_compare() that should be private to libreadline()

implementation.
- Add symlink /usr/include/edit/readline/tilde.h -> readline.h

All this makes it possible to build and link gdb with -ledit.

lib/libedit/edit/readline/Makefile

@@ -2,6 +2,7 @@
 # $FreeBSD$
 
 INCS=	readline.h history.h
+SYMLINKS=	readline.h ${INCLUDEDIR}/edit/readline/tilde.h
 
 INCSDIR= ${INCLUDEDIR}/edit/readline
 

lib/libedit/edit/readline/readline.h

@@ -200,7 +200,6 @@ void		 rl_get_screen_size(int *, int *);
 void		 rl_set_screen_size(int, int);
 char 		*rl_filename_completion_function (const char *, int);
 int		 _rl_abort_internal(void);
-int		 _rl_qsort_string_compare(char **, char **);
 char 	       **rl_completion_matches(const char *, rl_compentry_func_t *);
 void		 rl_forced_update_display(void);
 int		 rl_set_prompt(const char *);