lavfi: port 2xsai filter from libmpcodecs

Partially based on the port by Niel van der Westhuizen
<nielkie@gmail.com>, done for GCI 2010. Same output as the original
filter and as fast.

See thread:
Subject: [FFmpeg-devel] [PATCH] Port MPlayer 2xSaI filter to libavfilter
Date: Thu, 25 Nov 2010 01:31:24 +1000

1 files changed, 1 insertions, 0 deletions

diff --git a/configure b/configure
index 419d2526e1..3c0cd7b47c 100755
--- a/configure
+++ b/configure
@@ -1692,6 +1692,7 @@ ocv_filter_deps="libopencv"
 pan_filter_deps="swresample"
 removelogo_filter_deps="avcodec avformat swscale"
 scale_filter_deps="swscale"
+super2xsai_filter_deps="gpl"
 tinterlace_filter_deps="gpl"
 yadif_filter_deps="gpl"