Add CI compiling rustc

Author: antoyo

.github/workflows/nightly_rustc.yml

@@ -0,0 +1,66 @@
+name: Nightly compilation of rustc with rustc_codegen_gcc
+
+on:
+  pull_request:
+  # TODO: remove pull_request and add schedule to run during the night.
+
+env:
+  # Enable backtraces for easier debugging
+  RUST_BACKTRACE: 1
+
+jobs:
+  build:
+    runs-on: ubuntu-24.04
+
+    strategy:
+      fail-fast: false
+      matrix:
+        arch:
+          - host_target: "x86_64-unknown-linux-gnu"
+            gcc_urls: >
+              https://github.com/rust-lang/gcc/releases/latest/download/gcc-15.deb
+          - host_target: "m68k-unknown-linux-gnu"
+            gcc_urls: >
+              https://github.com/rust-lang/gcc/releases/latest/download/gcc-15.deb
+              https://github.com/cross-cg-gcc-tools/cross-gcc/releases/latest/download/gcc-m68k-15.deb
+
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        path: "rustc_codegen_gcc"
+
+    - uses: actions/checkout@v4
+      with:
+        repository: "rust-lang/rust"
+        path: "rust"
+        fetch-depth: 10
+
+    - run: |
+        ls
+        echo "*****"
+        ls ..
+        echo "*****"
+        ls rust
+        echo "*****"
+
+    # `rustup show` installs from rust-toolchain.toml
+    - name: Setup rust toolchain
+      run: rustup show
+
+    - name: Setup rust cache
+      uses: Swatinem/rust-cache@v2
+
+    - name: Download and install artifacts
+      run: |
+        urls=(${{ matrix.arch.gcc_urls }})
+        for url in "${urls[@]}"; do
+            curl -L -o package.deb $url
+            sudo dpkg --force-overwrite -i package.deb
+        done
+
+    # TODO: patch linux-raw-sys and rustix.
+
+    - name: Compile rustc
+      run: |
+        cd rust
+        ./x build --host=${{ matrix.arch.host_target }} --stage 2 --config ../rustc_codegen_gcc/tests/bootstraps/bootstrap.${{ matrix.arch.host_target }}.toml

tests/bootstraps/bootstrap.m68k-unknown-linux-gnu.toml

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+profile = "compiler"
+change-id = 140732
+
+[build]
+target = ["m68k-unknown-linux-gnu"]
+
+[rust]
+codegen-backends = ["gcc"]
+deny-warnings = false
+debug-assertions = false
+debug-assertions-std = false
+
+[gcc]
+download-ci-gcc = true
+libgccjit-libs-dir = "/home/runner/libgccjit-libs-dir"
+
+[target.m68k-unknown-linux-gnu]
+cc = "/home/runner/work/rustc_codegen_gcc/rustc_codegen_gcc/cross-gcc/usr/bin/m68k-unknown-linux-gnu-gcc"

tests/bootstraps/bootstrap.x86_64-unknown-linux-gnu.toml

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+profile = "compiler"
+change-id = 140732
+
+[rust]
+codegen-backends = ["gcc"]
+deny-warnings = false
+debug-assertions = false
+debug-assertions-std = false
+
+[gcc]
+download-ci-gcc = true