Bug#1086702: llvm-toolchain-19: FTBFS: Could not find wasi-libc on the system

[Duetsch, Thomas]

> Do you have more details about the context?
>
> https://buildd.debian.org/status/logs.php?pkg=llvm-toolchain-19&arch=arm64
>
> it has been ok here for a while :)
>
> Cheers
>
> S

I've seen that as well. I can't really explain why, but what we do when recompiling is the following:
We run the latest debian:trixie container and execute these commands.
---

# add deb-src
sed -i  "s/Types: deb/Types: deb deb-src/g"  /etc/apt/sources.list.d/debian.sources
apt-get update
apt-get upgrade -y
apt-get install -y --no-install-recommends devscripts equivs
apt-get source llvm-toolchain-19
cd llvm-toolchain-19-19.1.2/
mk-build-deps --install --remove
---

That leaves you with this list of dependencies to be installed:
---
The following NEW packages will be installed:
  binutils-dev build-essential chrpath cmake cmake-data dh-exec dh-ocaml diffstat docutils-common doxygen fonts-mathjax g++ g++-14 g++-14-aarch64-linux-gnu g++-aarch64-linux-gnu hello help2man
  icu-devtools lcov libabsl-dev libabsl20230802 libalgorithm-c3-perl libarchive13t64 libb-hooks-endofscope-perl libbigarray-compat-ocaml libbigarray-compat-ocaml-dev libbrotli-dev libbrotli1
  libbsd-dev libc-ares-dev libcapture-tiny-perl libcares2 libclang-cpp19 libclang1-19 libclass-c3-perl libclass-data-inheritable-perl libclass-inspector-perl libclass-singleton-perl
  libcompiler-libs-ocaml-dev libconfig-tiny-perl libctypes-ocaml libctypes-ocaml-dev libcurl4-openssl-dev libcurl4t64 libdata-optlist-perl libdatetime-locale-perl libdatetime-perl
  libdatetime-timezone-perl libdevel-stacktrace-perl libedit-dev libedit2 libelf-dev libeval-closure-perl libevent-2.1-7t64 libexception-class-perl libexpat1-dev libffi-dev libfile-sharedir-perl
  libfindlib-ocaml libfmt9 libgmp-dev libgmpxx4ldbl libgnutls-dane0t64 libgnutls-openssl27t64 libgnutls28-dev libgrpc++-dev libgrpc++1.51t64 libgrpc-dev libgrpc29t64 libicu-dev libidn2-dev
  libintegers-ocaml libintegers-ocaml-dev libjs-jquery libjs-mathjax libjs-sphinxdoc libjs-underscore libjson-perl libjsoncpp-dev libjsoncpp26 libllvm19 liblocale-gettext-perl libmd-dev
  libmodule-implementation-perl libmro-compat-perl libnamespace-autoclean-perl libnamespace-clean-perl libncurses-dev libncurses6 libnghttp2-14 libnghttp2-dev libp11-kit-dev
  libpackage-stash-perl libparams-util-perl libparams-validationcompiler-perl libperlio-gzip-perl libpfm4 libpfm4-dev libpkgconf3 libproc2-0 libprotobuf-dev libprotobuf-lite32t64
  libprotobuf32t64 libprotoc32t64 libpsl-dev libpsl5t64 libpython3-dev libpython3.12-dev libpython3.12t64 libre2-11 libre2-dev librhash1 librtmp-dev librtmp1 libspecio-perl libssh2-1-dev
  libssh2-1t64 libssl-dev libstdc++-14-dev libstdlib-ocaml libstdlib-ocaml-dev libsub-exporter-perl libsub-exporter-progressive-perl libsub-identify-perl libsub-install-perl libsub-name-perl
  libtasn1-6-dev libtext-unidecode-perl libunbound8 libuv1t64 libvariable-magic-perl libxapian30 libxml-libxml-perl libxml-namespacesupport-perl libxml-sax-base-perl libxml-sax-perl libxml2-dev
  libxstring-perl libyaml-0-2 libz3-4 libz3-dev libzstd-dev lsb-release nettle-dev ninja-build ocaml ocaml-base ocaml-findlib ocaml-interp pkg-config pkgconf pkgconf-bin procps protobuf-compiler
  protobuf-compiler-grpc python-babel-localedata python3-alabaster python3-autocommand python3-babel python3-certifi python3-chardet python3-charset-normalizer python3-defusedxml python3-dev
  python3-docutils python3-idna python3-imagesize python3-inflect python3-jaraco.context python3-jaraco.functools python3-jinja2 python3-markdown-it python3-markupsafe python3-mdit-py-plugins
  python3-mdurl python3-more-itertools python3-myst-parser python3-packaging python3-pexpect python3-pkg-resources python3-ptyprocess python3-pygments python3-requests python3-roman
  python3-setuptools python3-snowballstemmer python3-sphinx python3-typeguard python3-typing-extensions python3-urllib3 python3-yaml python3-zipp python3.12-dev sgml-base sharutils sphinx-common
  swig tex-common texinfo texinfo-lib time ucf xml-core zlib1g-dev
---

Notably it installs "hello", but not "wasi-libc" (same goes for the spirv packages). Somehow the resolution seems to be different than on the official build server in that it installs hello because of the g++-multilib line and then does not install any of the other packages, because hello satisfies the build-dep already, as described in the comment, I think.
The command "apt-get build-dep --only-source llvm-toolchain-19" yields the same result.

After that, the build fails with the mentioned error message.

Cheers,
Thomas