posix: No longer adjust stack size. It can screw up third party libs
Rewrite VDPAU implementation

Now works again after libav10 upgrade.

Also use the VDPAU OpenGL interop GL extension to avoid X11 pixmap hacks.
The old hack would cause tearing on high res displays

New implementation also support mid-stream resolution switching and switching
back/forth between software decoding and accelerated decoding
fa/smb: Fix use after free