print the compiler version in CI, for help with debugging

.github/workflows/ci.yml

@@ -33,8 +33,14 @@ jobs:
         toolchain: ${{ format('{0}-{1}', matrix.channel, matrix.target.toolchain) }}
         profile: minimal
         override: true
+    # Print the compiler version, for debugging.
+    - name: print compiler version
+      run: cargo run --quiet
+      working-directory: ./tools/compiler_version
     # Print out instruction set support, for debugging.
-    - run: cargo run --quiet --bin instruction_set_support
+    - name: print instruction set support
+      run: cargo run --quiet
+      working-directory: ./tools/instruction_set_support
     # Default tests plus Rayon.
     - run: cargo test --features=rayon
     # no_std tests.

tools/compiler_version/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "compiler_version"
+version = "0.0.0"
+edition = "2018"
+
+[build-dependencies]
+cc = "1.0.50"

tools/compiler_version/build.rs

@@ -0,0 +1,6 @@
+fn main() {
+    let build = cc::Build::new();
+    let compiler = build.get_compiler();
+    let compiler_path = compiler.path().to_string_lossy();
+    println!("cargo:rustc-env=COMPILER_PATH={}", compiler_path);
+}

tools/compiler_version/src/main.rs

@@ -0,0 +1,12 @@
+fn main() {
+    // Set in build.rs.
+    let compiler_path = env!("COMPILER_PATH");
+
+    let mut compiler_command = std::process::Command::new(compiler_path);
+    // Use the --version flag on everything other than MSVC.
+    if !cfg!(target_env = "msvc") {
+        compiler_command.arg("--version");
+    }
+    // Run the compiler to print its version. Ignore the exit status.
+    let _ = compiler_command.status().unwrap();
+}

tools/instruction_set_support/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "instruction_set_support"
+version = "0.0.0"
+edition = "2018"
+
+[dependencies]