configure: depend on babl 0.1.40 or newer

app/sanity.c

@@ -480,7 +480,7 @@ sanity_check_babl (void)
 
 #define BABL_REQUIRED_MAJOR 0
 #define BABL_REQUIRED_MINOR 1
-#define BABL_REQUIRED_MICRO 38
+#define BABL_REQUIRED_MICRO 40
 
   babl_get_version (&babl_major_version,
                     &babl_minor_version,

configure.ac

@@ -43,7 +43,7 @@ m4_define([gimp_stable],
 m4_define([gimp_full_name], [GNU Image Manipulation Program])
 
 # required versions of other packages
-m4_define([babl_required_version], [0.1.38])
+m4_define([babl_required_version], [0.1.40])
 m4_define([gegl_required_version], [0.3.27])
 m4_define([glib_required_version], [2.54.2])
 m4_define([atk_required_version], [2.2.0])