[gegl] build: adjust ffmpeg library dependencies

[Øyvind Kolås <ok src gnome org>]

commit 7ce5f3b902c0399ff4b62d2a84c57ab1ae03bc59
Author: Øyvind Kolås <pippin gimp org>
Date:   Tue Feb 16 16:26:30 2016 +0100

    build: adjust ffmpeg library dependencies
    
    These versions correspond to ffmpeg-2.3, as of 2015-12-15

 configure.ac |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 624497f..e3aa6cb 100644
--- a/configure.ac
+++ b/configure.ac
@@ -61,9 +61,9 @@ m4_define([poly2tri-c_required_version], [0.0.0])
 m4_define([pygobject2_required_version], [2.26])
 m4_define([pygobject3_required_version], [3.2])
 m4_define([vapigen_required_version], [0.20.0])
-m4_define([libavformat_required_version], [56.0.0])
-m4_define([libavcodec_required_version], [56.34.1])
-m4_define([libswscale_required_version], [3.1.0])
+m4_define([libavformat_required_version], [55.48.100])
+m4_define([libavcodec_required_version], [55.69.100])
+m4_define([libswscale_required_version], [2.6.100])
 
 AC_INIT(gegl, gegl_major_version.gegl_minor_version.gegl_micro_version)