This patch needs to be submitted to the libffi project. Also, the ChangeLog needs to specify exactly what is being changed not "Implement Go Closures". The patch clearly touches existing parts of the files that affect more than simply Go closures.
How was this tested? libffi is used in many more places than Go, so any changes need to be tested very carefully and thoroughly. What are the results for the libffi testsuite? Have you tried building Python with a version of libffi built with this patch? Thanks, David
