Merge commit '61b323ce7c7cdc101eadfd7de2203922b8a39e8d'

* commit '61b323ce7c7cdc101eadfd7de2203922b8a39e8d':
  vf_frei0r: refactor library loading from env variable

Conflicts:
	configure
	libavfilter/vf_frei0r.c

Not merged, we use av_strtok() which leads to simpler code

Merged-by: Michael Niedermayer <michaelni@gmx.at>