Index: cffi-1.15.1/c/_cffi_backend.c
===================================================================
--- cffi-1.15.1.orig/c/_cffi_backend.c
+++ cffi-1.15.1/c/_cffi_backend.c
@@ -87,7 +87,7 @@
  * This is also used on macOS, provided we are executing on macOS 10.15 or
  * above.  It's a mess because it needs runtime checks in that case.
  */
-#ifdef __NetBSD__
+#if defined(__NetBSD__) || (defined(__APPLE__) && !defined(FFI_AVAILABLE_APPLE))
 
 # define CFFI_CHECK_FFI_CLOSURE_ALLOC 1
 # define CFFI_CHECK_FFI_CLOSURE_ALLOC_MAYBE 1