API: Add libusb_free_pollfds() function

This patch adds a new API call to ensure that the same memory
allocator is used to both allocate and free the list of libusb_pollfd
structures. It is an incorrect assumption that the user's free() will
use the same memory allocator that libusb uses internally.

Signed-off-by: Chris Dickens <christopher.a.dickens@gmail.com>
4 files changed