This is the newest version currently available in the Ubuntu 24.04
repos.
This fixes building; previously it failed to build libc++, which only
supports being built with one of the two preceding versions of Clang.
This reverts commit 490dfffb32.
This is no longer necessary, as we now can build runtimes using
the latest LLVM 19 versions, that support building sanitizers
for all architectures.
Update to using clang-18 from the host system; version 16 or
newer is required for the implicitly selected config files
(which are used since 866d47cced);
that version changed whether the target triples are normalized
before locating config files.
This allows building runtimes with the current versions of LLVM
19.x, rather than needing to select an older version.
This is one of the packages which aren't needed by the toolchain
build itself, but is provided as a convenience to useres of the image.
Many projects that build standalone x86 assembly can use either
nasm or yasm, but lately most projects prefer nasm (which has
support for newer x86 simd extensions).
In Ubuntu 24.04, this package is no longer available.
However, this package probably never actually was needed anyway,
and was probably only provided as a convenience for users of the
docker image.
Martin Storsjö