Bug#1020802: libz3-4: Xorg crashes on startup due to illegal instruction (SSE2) in libz3-4

[Russ Dill]

> The package pulling in libz3-4 into the dependency chain is libllvm14.
> I've noticed the ubuntu version of the package does not link against
> libz3-4 and the libz3-4 package can be removed from the system and
> xorg and mesa function just fine. Perhaps a version of libllvm14
> compiled without libz3-4 support that could be installed on instead or
> even along side?

A look at the control file for libllvm14 gives a little more detail:

Z3_FLAG = -DLLVM_ENABLE_Z3_SOLVER=OFF
ifeq ($(shell dpkg --compare-versions $(shell dpkg-query -W -f
'$${Version}' libz3-dev) gt 4.7.0; echo $$?),0)
# no ocaml support in main for Ubuntu
ifneq ($(shell dpkg-vendor --derives-from Ubuntu && echo yes),yes)
        Z3_FLAG = -DLLVM_ENABLE_Z3_SOLVER=ON
endif
endif
STAGE_2_CMAKE_EXTRA += $(Z3_FLAG)

https://www.cambus.net/clang-static-analyzer-and-the-z3-constraint-solver/

I'm pretty sure the "no ocaml support in main for Ubuntu" is in error
and should read "no z3 constraint solver support in main for Ubuntu".
The author seems to have gotten the similarly named z3 constraint
solver and the LLVM backend for ocaml (Z3) confused.

https://github.com/ohmi/Z3