apollo_compilation_utils: add verify_compiler_binary

New function that checks a compiler binary's version at runtime and
panics with installation instructions if missing or wrong version.
Added alongside the existing install_compiler_binary — no callers yet.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: avi-starkware

crates/apollo_compilation_utils/src/build_utils.rs

@@ -1,3 +1,4 @@
+use std::path::Path;
 use std::process::Command;
 
 use tempfile::TempDir;
@@ -64,3 +65,27 @@ pub fn install_compiler_binary(
 
     println!("Successfully set executable file: {:?}", binary_path.display());
 }
+
+/// Verifies that a compiler binary is installed and has the required version.
+/// Panics with installation instructions if the binary is missing or has the wrong version.
+pub fn verify_compiler_binary(binary_path: &Path, required_version: &str) {
+    let binary_name = binary_path.display();
+    match Command::new(binary_path).arg("--version").output() {
+        Ok(output) => {
+            let version_str = String::from_utf8_lossy(&output.stdout);
+            if !version_str.contains(required_version) {
+                panic!(
+                    "{binary_name} version {required_version} is required, but found: \
+                     {version_str}. Run 'scripts/install_compiler_binaries.sh' to install the \
+                     correct version."
+                );
+            }
+        }
+        Err(_) => {
+            panic!(
+                "{binary_name} not found. Run 'scripts/install_compiler_binaries.sh' to install \
+                 it."
+            );
+        }
+    }
+}