[gegl] configure: specify minimum versions for exr, sdl, png and webp

[Øyvind Kolås <ok src gnome org>]

commit 4e2f6732e9ac825ab6f689926dd4baa6c4c40b5b
Author: Øyvind Kolås <pippin gimp org>
Date:   Mon Oct 9 13:10:29 2017 +0200

    configure: specify minimum versions for exr, sdl, png and webp

 configure.ac |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index a1d51c0..25f412f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -50,13 +50,13 @@ m4_define([lensfun_required_version], [0.2.5])
 m4_define([librsvg_required_version], [2.40.6])
 m4_define([libv4l2_required_version], [1.0.1])
 m4_define([lua_required_version], [5.1.0])
-m4_define([openexr_required_version], [0.0.0])
+m4_define([openexr_required_version], [1.6.1])
 m4_define([libraw_required_version], [0.15.4])
 m4_define([pango_required_version], [1.38.0])
-m4_define([png_required_version], [0.0.0])
-m4_define([sdl_required_version], [0.0.0])
+m4_define([png_required_version], [1.6.0])
+m4_define([sdl_required_version], [1.2.0])
 m4_define([libtiff_required_version], [4.0.0])
-m4_define([webp_required_version], [0.0.0])
+m4_define([webp_required_version], [0.5.0])
 m4_define([poly2tri-c_required_version], [0.0.0])
 m4_define([pygobject2_required_version], [2.26])
 m4_define([pygobject3_required_version], [3.2])