Rollup merge of #133801 - Gelbpunkt:powerpc64le-unknown-linux-musl-tier-2, r=jieyouxu,Urgau,Kobzol

Promote powerpc64le-unknown-linux-musl to tier 2 with host tools

MCP: https://github.com/rust-lang/compiler-team/issues/803

I'm using crosstool-ng for building a toolchain because GCC 9 from `musl-toolchain.sh` has float ABI issues (?) and can't compile LLVM, and writing a crosstool-ng config for a target feels less hacky than yet another target specific shell script. I also defined a kernel version, since there wasn't one specified before. If a lower version is desired, just let me know. I also tried to match the rust configure args with the loongarch64 musl tier 2 target.

The resulting compiler works fine, built with `DEPLOY=1 ./src/ci/docker/run.sh dist-powerpc64le-linux` and tested on Alpine Linux in a VM and on a bare metal POWER8 machine:
```
qemu-ppc64le:/tmp/rust-nightly-powerpc64le-unknown-linux-musl$ ash install.sh
install: creating uninstall script at /usr/local/lib/rustlib/uninstall.sh
install: installing component 'rustc'
install: installing component 'rust-std-powerpc64le-unknown-linux-musl'
install: installing component 'cargo'
install: installing component 'rustfmt-preview'
install: installing component 'rls-preview'
install: installing component 'rust-analyzer-preview'
install: installing component 'llvm-tools-preview'
install: installing component 'clippy-preview'
install: installing component 'miri-preview'
install: installing component 'rust-analysis-powerpc64le-unknown-linux-musl'
install: installing component 'llvm-bitcode-linker-preview'
install: WARNING: failed to run ldconfig. this may happen when not installing as root. run with --verbose to see the error

    rust installed.

qemu-ppc64le:~$ echo 'fn main() { println!("hello world"); }' > test.rs
qemu-ppc64le:~$ rustc test.rs
qemu-ppc64le:~$ ./test
hello world
qemu-ppc64le:~$ file test
test: ELF 64-bit LSB executable, 64-bit PowerPC or cisco 7500, OpenPOWER ELF V2 ABI, version 1 (SYSV), statically linked, BuildID[sha1]=596ee6abf9add487ebc54fb71c2076fb6faea013, with debug_info, not stripped
```

try-job: dist-powerpc64le-linux

2 files changed, 43 insertions, 4 deletions

diff --git a/src/ci/docker/host-x86_64/dist-powerpc64le-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-powerpc64le-linux/Dockerfile
index 5dc282403be..9ef39189249 100644
--- a/src/ci/docker/host-x86_64/dist-powerpc64le-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-powerpc64le-linux/Dockerfile
@@ -3,23 +3,46 @@ FROM ubuntu:22.04
 COPY scripts/cross-apt-packages.sh /scripts/
 RUN sh /scripts/cross-apt-packages.sh
 
+COPY scripts/crosstool-ng-git.sh /scripts/
+RUN sh /scripts/crosstool-ng-git.sh
+
 COPY scripts/rustbuild-setup.sh /scripts/
 RUN sh /scripts/rustbuild-setup.sh
+
 WORKDIR /tmp
 
+COPY scripts/crosstool-ng-build.sh /scripts/
+COPY host-x86_64/dist-powerpc64le-linux/powerpc64le-unknown-linux-musl.defconfig /tmp/crosstool.defconfig
+RUN /scripts/crosstool-ng-build.sh
+
+WORKDIR /build
+
 RUN apt-get install -y --no-install-recommends rpm2cpio cpio
-COPY host-x86_64/dist-powerpc64le-linux/shared.sh host-x86_64/dist-powerpc64le-linux/build-powerpc64le-toolchain.sh /tmp/
+COPY host-x86_64/dist-powerpc64le-linux/shared.sh host-x86_64/dist-powerpc64le-linux/build-powerpc64le-toolchain.sh /build/
 RUN ./build-powerpc64le-toolchain.sh
 
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+ENV PATH=$PATH:/x-tools/powerpc64le-unknown-linux-musl/bin
+
 ENV \
     AR_powerpc64le_unknown_linux_gnu=powerpc64le-linux-gnu-ar \
     CC_powerpc64le_unknown_linux_gnu=powerpc64le-linux-gnu-gcc \
-    CXX_powerpc64le_unknown_linux_gnu=powerpc64le-linux-gnu-g++
+    CXX_powerpc64le_unknown_linux_gnu=powerpc64le-linux-gnu-g++ \
+    AR_powerpc64le_unknown_linux_musl=powerpc64le-unknown-linux-musl-ar \
+    CC_powerpc64le_unknown_linux_musl=powerpc64le-unknown-linux-musl-gcc \
+    CXX_powerpc64le_unknown_linux_musl=powerpc64le-unknown-linux-musl-g++
+
+ENV HOSTS=powerpc64le-unknown-linux-gnu,powerpc64le-unknown-linux-musl
 
-ENV HOSTS=powerpc64le-unknown-linux-gnu
+ENV RUST_CONFIGURE_ARGS \
+    --enable-extended \
+    --enable-full-tools \
+    --enable-profiler \
+    --enable-sanitizers \
+    --disable-docs \
+    --set target.powerpc64le-unknown-linux-musl.crt-static=false \
+    --musl-root-powerpc64le=/x-tools/powerpc64le-unknown-linux-musl/powerpc64le-unknown-linux-musl/sysroot/usr
 
-ENV RUST_CONFIGURE_ARGS --enable-extended --enable-profiler --disable-docs
 ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS
diff --git a/src/ci/docker/host-x86_64/dist-powerpc64le-linux/powerpc64le-unknown-linux-musl.defconfig b/src/ci/docker/host-x86_64/dist-powerpc64le-linux/powerpc64le-unknown-linux-musl.defconfig
new file mode 100644
index 00000000000..c6cde30b2a4
--- /dev/null
+++ b/src/ci/docker/host-x86_64/dist-powerpc64le-linux/powerpc64le-unknown-linux-musl.defconfig
@@ -0,0 +1,16 @@
+CT_CONFIG_VERSION="4"
+CT_EXPERIMENTAL=y
+CT_PREFIX_DIR="/x-tools/${CT_TARGET}"
+CT_USE_MIRROR=y
+CT_MIRROR_BASE_URL="https://ci-mirrors.rust-lang.org/rustc"
+CT_ARCH_POWERPC=y
+CT_ARCH_LE=y
+CT_ARCH_64=y
+# CT_DEMULTILIB is not set
+CT_ARCH_ARCH="powerpc64le"
+CT_KERNEL_LINUX=y
+CT_LINUX_V_4_19=y
+CT_LIBC_MUSL=y
+CT_MUSL_V_1_2_3=y
+CT_CC_LANG_CXX=y
+CT_GETTEXT_NEEDED=y