away the string to add_history.
(completion_function): Do completion for readline.
(scm_filename_completion_function): New procedure: Filename
completer.
(current_input_getc): New function. Use this one instead of
standard getc from readline.
* readline.c, readline.h: New files.
* init.c: #include "readline.h".
(scm_boot_guile_1): Call scm_init_readline, if we have it.
* Makefile.am (libguile_la_SOURCES): Include readline.c.
* Makefile.in: Regenerated.
* scmconfig.h.in: Regenerated, after change to ../configure.