With this, user applications which use custom IO and have set a IO context will not have
their already opened IO context ignored and glob/seq being interpreted

Comments and tests from maintainers of user apps are welcome!
Liked-by: wm4 <nfxjfg@googlemail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 7ccedc1c)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>