There is a new upstream version 0.67 of yosys.  I tried to package it
for Debian experimental, but failed.  The main reason is that the
upstream git repository have changed to using git submodules of the
embedded libraries, but it also did not help that the build system have
been changed from autoconf/make to cmake, making several of the existing
patches to no longer apply.

The git submodule approach is not compatible with the recipe in
debian/README.source on how to get the latest upstream source (gbp
import-orig --component=abc --uscan), as this do not import the
submodules in libs/, and thus the source do not have all the source it
need to build.

The replaced build system invalidate several Debian specific fixes like
getting autopkgtest working with the test suite in yosys and several
other patches.  These patches modify the no longer present Makefile and
thus need to be ported to cmake, if they are still needed:

  0001-Make-tests-runnable-standalone.patch
  0007-Disable-pretty-build.patch
  0010-Fix-adding-of-sys.path-in-yosys-smtbmc.patch
  0011-Do-not-show-g-build-flags-in-Version-string.patch
  0031-Set-pythonpath-for-usage-docs.patch

I do not understand cmake enough to do the change myself, and hope
someone else who understand cmake can have a look.

It looks like the Fedora and OpenSUSE yosys packagers are having
similar issues:

https://github.com/YosysHQ/yosys/issues/6028

Their approach is to ignore the bundled libraries and using existing
packages or packaging the libraries. This is probably the same path
Debian should follow.

boost_regex, cxxopts, fmt and tomlplusplus are already packaged so only
slang would be new. (The libslang2 packages are not the right slang).

I think most of the Makefile patches can just be dropped, rather than
ported to cmake as there should be much less scripting which is what
needed to be changed.
If you get some sort of build working then lintian and the reproducible
build tools will soon spot if something needs to be addressed.

Cheers,
Scott