Meta: Migrate find_compiler.sh logic to a python script

This will allow us to re-use this logic from within other python
scripts. The find_compiler.sh script still exists, as it is used by
some other bash scripts. The pick_host_compiler() function will now
execute find_compiler.py and store its result in $CC and $CXX.

Note that the python script supports Windows.

Meta/utils.py

@@ -0,0 +1,41 @@
+# Copyright (c) 2025, Tim Flynn <trflynn89@ladybird.org>
+#
+# SPDX-License-Identifier: BSD-2-Clause
+
+import signal
+import subprocess
+import sys
+
+from typing import Optional
+from typing import Union
+
+
+def run_command(
+    command: list[str],
+    input: Union[str, None] = None,
+    return_output: bool = False,
+    exit_on_failure: bool = False,
+) -> Optional[str]:
+    stdin = subprocess.PIPE if type(input) is str else None
+    stdout = subprocess.PIPE if return_output else None
+
+    try:
+        # FIXME: For Windows, set the working directory so DLLs are found.
+        with subprocess.Popen(command, stdin=stdin, stdout=stdout, text=True) as process:
+            (output, _) = process.communicate(input=input)
+
+            if process.returncode != 0:
+                if exit_on_failure:
+                    sys.exit(process.returncode)
+                return None
+
+    except KeyboardInterrupt:
+        process.send_signal(signal.SIGINT)
+        process.wait()
+
+        sys.exit(process.returncode)
+
+    if return_output:
+        return output.strip()
+
+    return None