Fix for issue9662, patch by Łukasz Langa in issue5504.

Modules/_ctypes/callbacks.c

@@ -416,9 +416,13 @@ CThunkObject *_ctypes_alloc_callback(PyObject *callable,
                      "ffi_prep_cif failed with %d", result);
         goto error;
     }
+#if defined(X86_DARWIN) || defined(POWERPC_DARWIN)
+    result = ffi_prep_closure(p->pcl_write, &p->cif, closure_fcn, p);
+#else
     result = ffi_prep_closure_loc(p->pcl_write, &p->cif, closure_fcn,
 				  p,
 				  p->pcl_exec);
+#endif
     if (result != FFI_OK) {
         PyErr_Format(PyExc_RuntimeError,
                      "ffi_prep_closure failed with %d", result);

Modules/_ctypes/libffi_osx/include/ffi.h

@@ -264,6 +264,9 @@ ffi_prep_closure(
 	void			(*fun)(ffi_cif*,void*,void**,void*),
 	void*			user_data);
 
+void ffi_closure_free(void *);
+void *ffi_closure_alloc (size_t size, void **code);
+
 typedef struct ffi_raw_closure {
 	char		tramp[FFI_TRAMPOLINE_SIZE];
 	ffi_cif*	cif;

Modules/_ctypes/malloc_closure.c

@@ -109,4 +109,3 @@ void *ffi_closure_alloc(size_t ignored, void** codeloc)
     *codeloc = (void *)item;
     return (void *)item;
 }
-

setup.py

@@ -1657,6 +1657,7 @@ class PyBuildExt(build_ext):
         depends = ['_ctypes/ctypes.h']
 
         if sys.platform == 'darwin':
+            sources.append('_ctypes/malloc_closure.c')
             sources.append('_ctypes/darwin/dlfcn_simple.c')
             extra_compile_args.append('-DMACOSX')
             include_dirs.append('_ctypes/darwin')