-20 not of type (UNSIGNED-BYTE 44) error when running McCLIM demos

[Paolo Amoroso]

On my Linux Mint system I updated SBCL from version 2.4.6 to 2.4.7 by installing the AMD64 binaries.

With SBCL 2.4.6 McCLIM worked fine. With version 2.4.7, loading the CLIM examples with `(ql:quickload :clim-examples)` completes with no errors:

* (ql:quickload :clim-examples)
To load "clim-examples":
  Load 1 ASDF system:
    clim-examples
; Loading "clim-examples"
..................................................
........................................
;; try (CLIM-DEMO:DEMODEMO)

(:CLIM-EXAMPLES)
*

However, evaluating `(clim-demo:demodemo)` yields the error `The value -20 is not of type (UNSIGNED-BYTE 44)` and no debugger prompt is available, so I have to terminate SBCL to regain control:

#<CLIM-DEMO:DEMODEMO {100440ADB3}>
*
debugger invoked on a TYPE-ERROR @B80028AF32 in thread
#<THREAD tid=11041 "DEMODEMO" RUNNING {1007063D13}>:
  The value
    -20
  is not of type
    (UNSIGNED-BYTE 44)
  when binding SB-IMPL::REMAINING-REQUEST

The current thread is not at the foreground,
SB-THREAD:RELEASE-FOREGROUND has to be called in #<SB-THREAD:THREAD tid=10974 "main thread" RUNNING {1000B80093}>
for this thread to enter the debugger.

I originally reported the issue https://codeberg.org/McCLIM/McCLIM/issues/1395 to the McCLIM project and did some troubleshooting, such as building upstream McCLIM and clearing the Lisp cache. However, the issue persists and I still get the same error.

`sbcl --version` returns `SBCL 2.4.7` and the output of `uname -a` is:

Linux lispmachine 6.9.3-76060903-generic #202405300957~1718348209~22.04~7817b67~dev-Ubuntu SMP PREEMPT_DY x86_64 x86_64 x86_64 GNU/Linux

The value of `*FEATURES*` is:

(:QUICKLISP :ASDF3.3 :ASDF3.2 :ASDF3.1 :ASDF3 :ASDF2 :ASDF :OS-UNIX
 :NON-BASE-CHARS-EXIST-P :ASDF-UNICODE :ARENA-ALLOCATOR :X86-64 :GENCGC :64-BIT
 :ANSI-CL :COMMON-LISP :ELF :IEEE-FLOATING-POINT :LINUX :LITTLE-ENDIAN
 :PACKAGE-LOCAL-NICKNAMES :SB-LDB :SB-PACKAGE-LOCKS :SB-THREAD :SB-UNICODE
 :SBCL :UNIX)