With LLVM 23 bundled, a sysroot still on libc++ 22 without its own
module source (Alpine v3.24) is the mirror image of the case that
started this: the toolchain's source is a release ahead of the
sysroot's headers. The new libcxx-22-modules module installs libc++
22.1.8's module source under share/crafter-build/libc++-modules/22,
where SysrootStdModule looks for the release a sysroot is on.
It only configures libc++'s runtimes build and installs the cxx-modules
component: std.cppm as configure generates it and the .inc files from
the source tree, nothing compiled, about 600 KB installed. The
component is staged and copied because it also writes
lib/libc++.modules.json, which belongs to the bundled libc++.
Verified in the built Flatpak: `crafter-build --version` lists release
22, and a cross build against an Alpine v3.24 aarch64 sysroot (libc++
22.1.3) precompiles that source with clang 23, links and runs under
qemu.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Jorijn van der Graaf
4159ee4117