MacOS 11, arm64, ffi_prep_cif_var

On Apple arm64, theABI for a variardic function is different than the
ABI for a fixed-arg function, even of the same arg types.

In order to account for this, CFFI must call ffi_prep_cif_var for
variardic calls.

see: https://developer.apple.com/library/archive/documentation/Xcode/Conceptual/iPhoneOSABIReference/Articles/ARM64FunctionCallingConventions.html

1 files changed, 2 insertions, 1 deletions

diff --git a/setup.py b/setup.py
index c28147e..fc8d705 100644
--- a/setup.py
+++ b/setup.py
@@ -152,7 +152,8 @@ else:
     if 'darwin' in sys.platform and macosx_deployment_target() >= (10, 15):
         # use libffi from Mac OS SDK
         extra_compile_args += ['-iwithsysroot/usr/include/ffi']
-        define_macros += [('CFFI_TRUST_LIBFFI', '1')]
+        define_macros += [('CFFI_TRUST_LIBFFI', '1'),
+                          ('HAVE_FFI_PREP_CIF_VAR', '1')]
         libraries += ['ffi']
     else:
         use_pkg_config()