При попытке загрузить подсистему с помощью QuickLisp в SBCL получил ошибку следующего вида:
* (ql:quickload "chillax")

debugger invoked on a LOAD-SYSTEM-DEFINITION-ERROR in thread #
"initial thread" RUNNING
{1002928DA1}>:
Error while trying to load definition for system chillax from pathname
/home/user/quicklisp/dists/quicklisp/software/chillax-20110522-git/chillax.asd:

decoding error on stream
#
for "file /home/user/quicklisp/dists/quicklisp/software/chillax-20110522-git/chillax.asd"
{100386B081}>
(:EXTERNAL-FORMAT :ASCII):
the octet sequence (195) cannot be decoded.

Type HELP for debugger help, or (SB-EXT:QUIT) to exit from SBCL.

restarts (invokable by number or by possibly-abbreviated name):
0: [ATTEMPT-RESYNC ] Attempt to resync the stream at a character boundary
and continue.
1: [FORCE-END-OF-FILE] Force an end of file.
2: [INPUT-REPLACEMENT] Use string as replacement input, attempt to resync at
a character boundary and continue.
3: [ABORT ] Abort loading file "/home/user/quicklisp/dists/quicklisp/software/chillax-20110522-git/chillax.asd".
4: Give up on "chillax"
5: Exit debugger, returning to top level.

((FLET #:LAMBDA1713) #)
0] 5

Решение, быть может, не очень красивое, зато надежное:

помещаем в .sbclrc строку

(setf sb-impl::*default-external-format* :utf-8)