craig@lister:~$ gcc -lreadline -o readline_test readline_test.c 
/tmp/ccUwhRRZ.o: In function `main':
readline_test.c:(.text+0x10): undefined reference to `rl_get_keymap'
readline_test.c:(.text+0x18): undefined reference to `rl_get_keymap_name'
collect2: error: ld returned 1 exit status