[gegl] docs: Mention that json-glib is required dependency

[Jon Nordby <jonnor src gnome org>]

commit d5a2e82df7a10630507c1ee75f56019aa250bc8a
Author: Jon Nordby <jononor gmail com>
Date:   Tue Jan 20 17:24:30 2015 +0100

    docs: Mention that json-glib is required dependency

 docs/build.txt |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/docs/build.txt b/docs/build.txt
index 32bca75..7515dc4 100644
--- a/docs/build.txt
+++ b/docs/build.txt
@@ -25,6 +25,7 @@ other systems where glib and gtk+ work.
       * glib (including gobject, and gmodule) 2.32 or newer, which provides
         inheritance, dynamic modules, common algorithms and data structures
         for C programming.
+      * json-glib 1.0.0 or newer, for loading operations from .json format
       * http://gegl.org/babl/[babl] 0.1.10 or newer (for pixel-format
         agnostisism).
       * libpng (png load/export ops, and image magick fallback import)