their own version of scm_readline.
* readline.c, readline.h (rl_cleanup_after_signal,
rl_free_line_state): Made global.
(scm_readline_init_ports): New function.
(scm_readline): Use scm_readline_init_ports.
(Thanks to Anders Holst.)
rl_outstream on error before closing it.
* readline.c: #include "libguile/_scm.h" (so that we get the
configuration information) and fix other includes so that they'll
work on a system where guile is not yet installed.
