Importing cched (sagittarius debug) causes SEGV

[Takashi Kato]

(import (sagittarius debug)) causes SEGV if the library is cached.

This is because get-dispatch-macro-character on the toplevel. If the library is cached then current-loading-port returns NULL and getting reader table causes SEGV. It might be better to return the same value as current-input-port if the value is NULL.

[Takashi Kato]

Returning current input port if the loading port is not set. (Fixes #114)

→ <<cset 1a6ddea3b211>>