When I run afl-gcc-fast on any source file, it aborts with an error: "GCC
and plugin have incompatible versions, expected GCC 12.2.0, is 12.2.0"
This started occurring after updating to Debian 12.11, which included a
gcc-12 update.

I can confirm that this problem exists.
We are building busybox (from Sid) using latest afl++ and gcc-12 from
Bookworm and got the same problem:

/usr/bin/make -f /<<PKGBUILDDIR>>/scripts/Makefile.build obj=scripts/basic
/bin/bash /<<PKGBUILDDIR>>/scripts/mkmakefile \
    /<<PKGBUILDDIR>> /<<PKGBUILDDIR>>/b/deb 1 37
  GEN     /<<PKGBUILDDIR>>/b/deb/Makefile
printf '#ifndef __linux__\nplatform_is_not_linux\n#endif' \
    |  - | grep -s platform_is_not_linux \
  && linux=n || linux=y; \
printf "config PLATFORM_LINUX\n\tbool\n\tdefault $linux\n" > .platform.in
  afl-gcc-fast -Wp,-MD,scripts/basic/.fixdep.d -Iscripts/basic  -o
scripts/basic/fixdep /<<PKGBUILDDIR>>/scripts/basic/fixdep.c
/bin/sh: 2: -: not found
/<<PKGBUILDDIR>>/scripts/gen_build_files.sh /<<PKGBUILDDIR>>
/<<PKGBUILDDIR>>/b/deb

[-] PROGRAM ABORT : GCC and plugin have incompatible versions, expected GCC
12.2.0, is 12.2.0
         Location : plugin_init(), instrumentation/afl-gcc-pass.so.cc:482

make[4]: *** [scripts/Makefile.host:104: scripts/basic/fixdep] Error 1
make[3]: *** [/<<PKGBUILDDIR>>/Makefile:357: scripts_basic] Error 2
make[3]: *** Waiting for unfinished jobs....