[gegl] build: depend on babl-0.1.58

[Øyvind "pippin" Kolås <ok src gnome org>]

commit fa55a1800273486ffe44b2cb53a64184df7848a8
Author: Øyvind Kolås <pippin gimp org>
Date:   Fri Oct 5 16:23:30 2018 +0200

    build: depend on babl-0.1.58

 configure.ac | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/configure.ac b/configure.ac
index b324fa061..7ccbe3634 100644
--- a/configure.ac
+++ b/configure.ac
@@ -37,7 +37,7 @@ m4_define([gegl_stable],
 m4_define([gimp_full_name], [Generic Graphical Library])
 
 # required versions of external libraries
-m4_define([babl_required_version], [0.1.56])
+m4_define([babl_required_version], [0.1.58])
 m4_define([cairo_required_version], [1.12.2])
 m4_define([exiv2_required_version], [0.25])
 m4_define([gdk_pixbuf_required_version], [2.32.0])