always fails on non mms

The input is not neessarily trusted. Better safe than sorry.

Not activated by default, because of probable hard OpenSSL dependency
Note that expat is not mandatory to build it...

ASDCPlib in itself is BSD 3-clause

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

Otherwise would buffer a preroll + min track delay

Should avoid hiccups after seek

or pcr update could never happen

The variable is already created by this point.