[Bug-apl] Another build error on OSX

[Elias Mårtenson]

Here's another error that prevents building on OSX. Hopefully we can have
this one fixed for 1.4:

g++ -DHAVE_CONFIG_H -I. -I..     -rdynamic   -g -MT NamedObject.o -MD -MP
-MF .deps/NamedObject.Tpo -c -o NamedObject.o NamedObject.cc
clang: warning: argument unused during compilation: '-rdynamic'
Input.cc:124:28: error: use of undeclared identifier 'rl_hook_func_t'
        rl_startup_hook = (rl_hook_func_t
*)(Input::init_readline_control_C);
                           ^
Input.cc:124:44: error: expected expression
        rl_startup_hook = (rl_hook_func_t
*)(Input::init_readline_control_C);
                                           ^
Input.cc:409:4: error: use of undeclared identifier 'rl_crlf'
   rl_crlf();
   ^
Input.cc:410:4: error: use of undeclared identifier 'rl_delete_text'
   rl_delete_text(0, rl_end);
   ^
Input.cc:411:4: error: use of undeclared identifier 'rl_done'
   rl_done = 1;
   ^

Regards,
Elias