-Zcodegen-backend no longer works on `x.py install`ed rustc

[matthiaskrgr]

Summary

~/.rustup/toolchains/local-debug-assertions/bin/rustc dummy.rs -Zcodegen-backend=cranelift
error: failed to find a `codegen-backends` folder in the sysroot candidates:
       * /home/matthias/.rustup/toolchains/local-debug-assertions
       * /home/matthias/.rustup/toolchains/local-debug-assertions

Command used

RUSTFLAGS="-Zthreads=32" ./x.py  install  -j 16

Expected behaviour

it werky

Actual behaviour

it no werky :(

~/.rustup/toolchains/local-debug-assertions/bin/rustc dummy.rs -Zcodegen-backend=cranelift
error: failed to find a `codegen-backends` folder in the sysroot candidates:
       * /home/matthias/.rustup/toolchains/local-debug-assertions
       * /home/matthias/.rustup/toolchains/local-debug-assertions

Bootstrap configuration (bootstrap.toml)

change-id = 138934
[llvm]
download-ci-llvm = false
optimize = true
thin-lto = true
release-debuginfo = true
assertions = true
plugins = true
ninja = true
targets = "X86"
link-jobs = 4
cflags = "-march=native"
cxxflags = "-march=native"
ldflags = "-march=native"
[gcc]
[build]
submodules = true
extended = true
sanitizers = true
profiler = true
low-priority = true
[install]
prefix = "/home/matthias/.rustup/toolchains/local-debug-assertions"
sysconfdir = "/home/matthias/.rustup/toolchains/local-debug-assertions/etc"
[rust]
debug = true
debug-assertions = true
debug-assertions-std = true
overflow-checks = true
overflow-checks-std = true
dist-src = true
codegen-backends = ["llvm", "cranelift"]
use-lld = true
llvm-tools = true
deny-warnings = false
backtrace-on-ice = true
verify-llvm-ir = true
remap-debuginfo = true
lto = "thin"
validate-mir-opts = 3
[target.x86_64-unknown-linux-gnu]
[dist]
compression-formats = ["xz"]
compression-profile = "fast"

Operating system

Linux 6.13.8-2-MANJARO

HEAD

d3508a8

Additional context

Build Log

<log>

[Kobzol]

The CLIF backend has to be installed separately, using ./x install --set build.extended=true rustc-codegen-cranelift. However, that command is currently not working correctly. #146927 fixes that.