changes in sbcl-0.6.9 relative to sbcl-0.6.8:

* DESCRIBE now works on CONDITION objects.
* The debugger now handles errors which arise when trying to print
  *DEBUG-CONDITION*, so that it's less likely to fall into infinite
  regress.
* The build system now uses an additional file, customize-target-features.lisp,
  to allow local modifications to the target *FEATURES* list. (The point of
  this is that now I can set up a custom configuration, e.g. with :SB-SHOW
  debugging features enabled, without having to worry about propagating it
  into everyone's system when I do a "cvs update".) When no
  customize-target-features.lisp file exists, the target *FEATURES* list
  should be constructed the same way as before.
* fixed bugs in DEFCONSTANT ANSI-compatibility:
  ** DEFCONSTANT now tests reassignments using EQL, not EQUAL, in order to
     warn about behavior which is undefined under the ANSI spec. Note: This
     is specified by ANSI, but it's not very popular with programmers.
     If it causes you problems, take a look at the new SB-INT:DEFCONSTANT-EQX
     macro in the SBCL sources for an example of a workaround which you
     might use to make portable ANSI-standard code which does what you want.
  ** DEFCONSTANT's implementation is now based on EVAL-WHEN instead of on
     pre-ANSI IR1 translation magic, so it does the ANSI-specified thing
     when it's used as a non-toplevel form. (This is required in order
     to implement the DEFCONSTANT-EQX macro.)
  ** (DEFCONSTANT X 1) (DEFVAR X) (SETF X 2) no longer "works".
  ** Unfortunately, non-toplevel DEFCONSTANT forms can still do some
     funny things, due to bugs in the implementation of EVAL-WHEN
     (bug #IR1-3). This probably won't be fixed until 0.7.x. (Fortunately,
     non-toplevel DEFCONSTANTs are uncommon.)
* The core file version number and fasl file version number have been
  incremented, because the old noncompliant DEFCONSTANT behavior involved
  calling functions which no longer exist, and because I also took the
  opportunity to chop an unsupported slot out of the DEBUG-SOURCE structure.
* fixed bug 1 (error handling before read-eval-print loop starts), and
  redid debugger restarts and related debugger commands somewhat while
  doing so:
  ** The QUIT debugger command is gone, since it did something
     rather different than the SB-EXT:QUIT command, and since it never
     worked properly outside the main toplevel read/eval/print loop.
     Invoking the new TOPLEVEL restart provides the same functionality.
  ** The GO debugger command is also gone, since you can just invoke
     the CONTINUE restart directly instead.
  ** The TOP debugger command is also gone, since it's redundant with the
     FRAME 0 command, and since it interfered with abbreviations for the
     TOPLEVEL restart.
* The system now recovers better from non-PACKAGE values of the *PACKAGE*
  variable.
* The system now understands compound CONS types (e.g. (CONS FIXNUM T))
  as required by ANSI. (thanks to Douglas Crosher's CMU CL patches, with
  some porting work by Martin Atzmueller)
* Martin Atzmueller reviewed the CMU CL mailing lists and came back
  with a boatload of patches which he ported to SBCL. Now that those
  have been applied,
  ** The system tries to make sure that its low-priority messages
     are prefixed by semicolons, to help people who like to use
     syntax highlighting in their ILISP buffer. (This patch
     was originally due to Raymond Toy.)
  ** The system now optimizes INTEGER-LENGTH better, thanks to more
     patches originally written by Raymond Toy.
  ** The compiler understands coercion between single-value and
     multiple-VALUES type expressions better, getting rid of some very
     weird behavior, thanks to patches originally by Robert MacLachlan
     and Douglas Crosher.
  ** The system understands ANSI-style non-KEYWORD &KEY arguments in
     lambda lists, thanks to a patch originally by Pierre Mai.
  ** The system no longer bogusly warns about "abbreviated type
     declarations".
  ** The compiler gets less confused by inlining and RETURN-FROM,
     thanks to some patches originally by Tim Moore.
  ** The system no longer hangs when dumping circular lists to fasl
     files, thanks to a patch originally from Douglas Crosher.
* Martin Atzmueller also fixed ROOM, so that it no longer fails with an
  undefined function error.
* gave up on fixing bug 3 (forbidden-by-ANSI warning for type mismatch
  in structure slot initforms) for now, documented workaround instead:-|
* fixed bug 4 (no WARNING for DECLAIM FTYPE of slot accessor function)
* fixed bug 5: added stubs for various Gray stream functions called
  in the not-a-CL:STREAM case, so that even when Gray streams aren't
  installed, at least appropriate type errors are generated
* fixed bug 8: better reporting of various PROGRAM-ERRORs
* fixed bug 9: IGNORE and IGNORABLE now work reasonably and more
  consistently in DEFMETHOD forms.
* removed bug 21 from BUGS, since Martin Atzmueller points out that
  it doesn't seem to affect SBCL after all
* The C runtime system now builds with better optimization and many
  fewer warnings, thanks to lots of cleanups by Martin Atzmueller.