python/src/moocore/_ffi_build.py: Use LLVM for Windows ARM64.

Author: MLopez-Ibanez

python/src/moocore/_ffi_build.py

@@ -10,6 +10,8 @@
 
 import os
 import platform
+from distutils.core import Distribution
+from distutils import sysconfig
 from cffi import FFI
 
 # Compile in debug mode.
@@ -51,10 +53,7 @@
 
 
 def get_config():
-    from distutils.core import Distribution
-    from distutils.sysconfig import get_config_vars
-
-    get_config_vars()  # workaround for a bug of distutils, e.g. on OS/X
+    sysconfig.get_config_vars()  # workaround for a bug of distutils, e.g. on OS/X
     config = Distribution().get_command_obj("config")
     return config
 
@@ -73,15 +72,28 @@ def _get_target_platform():
     except ValueError:
         pass
 
-    return platform.machine()
+    arch = os.environ.get("CIBW_ARCH", platform.machine())
+    return arch
 
 
 is_windows = platform.system() == "Windows"
 is_macos = platform.system() == "Darwin"
-
 target_platform = _get_target_platform()
 is_x86_64 = target_platform in ("i686", "x86", "x86_64", "AMD64")
 
+if is_windows and target_platform == "ARM64":
+    os.environ["CC"] = "clang-cl"
+    os.environ["CXX"] = "clang-cl"
+    os.environ["LD"] = "lld-link"
+    # Prevent setuptools from re-enabling MSVC
+    os.environ["DISTUTILS_USE_SDK"] = "1"
+    os.environ["MSSdk"] = "1"
+    print("Using LLVM/clang-cl for Windows ARM64")
+else:
+    print(
+        f"Using default compiler {sysconfig.get_config_var('CC')} for arch={target_platform}"
+    )
+
 # Compiler flags.
 MSVC_CFLAGS = [
     "/O2",  # Maximize speed