:HISTORY and :KILLRING to LINEDIT &co can now be pathname
  designators.

 Use :IF-COMPOENNT-DEP-FAILS :TRY-NEXT in .asd for better system
 introspection.

 Add a "generic" port which only signals an error for INSTALL-REPL
 and UNINSTALL-REPL.

Modern versions of Osicat provide calls equivalent to signals.c, so we
can get rid of some UFFI cruft in preparation for migration to CFFI.
Also, /lib/terminfo/ added to *terminfo-directories* for modern Debian
systems.