delay importing ctypes unless it is actually used

ctypes uses FFI, and surprisingly often people's Python installations
will be broken because ctypes is broken (e.g. the system libffi has been
updated and Python needs to be recompiled). That is not our fault, but
it does manifest as Meson failing to run. It turns out we aren't even
using it though. At least, pretty often.

We have two uses of ctypes, and both of them are for Windows. One of
them is already conditionally imported in the function that uses it, but
the other is imported at startup. Move this down into the invoking
function.

On non-Windows systems, it is now impossible for Meson to fail to run
when ctypes is broken, because we don't use it. Anecdotally, this issue
tends to come up on Linux systems primarily.

Fixes #11111
Closes #11112

1 files changed, 1 insertions, 1 deletions

diff --git a/mesonbuild/utils/universal.py b/mesonbuild/utils/universal.py
index 220a7f4..a78ca7f 100644
--- a/mesonbuild/utils/universal.py
+++ b/mesonbuild/utils/universal.py
@@ -17,7 +17,6 @@
 from __future__ import annotations
 from pathlib import Path
 import argparse
-import ctypes
 import enum
 import sys
 import stat
@@ -699,6 +698,7 @@ def windows_detect_native_arch() -> str:
     if sys.platform != 'win32':
         return ''
     try:
+        import ctypes
         process_arch = ctypes.c_ushort()
         native_arch = ctypes.c_ushort()
         kernel32 = ctypes.windll.kernel32