* Fix macOS Big Sur crash with CVBufferCopyAttachments
Add FFmpeg patch to use weak_import for CVBufferCopyAttachments API
to prevent dyld crash on macOS Big Sur (11.x).
The CVBufferCopyAttachments function is only available on macOS 12+.
Even though FFmpeg has a runtime check with __builtin_available, the
symbol is still resolved at load time, causing immediate crash on older
macOS versions.
With weak_import attribute, the function pointer will be NULL on
macOS < 12, allowing the code to safely fall back to the deprecated
CVBufferGetAttachments API.
Fixes: #13377
* update common