[gimp] configure: output the list of missing dependencies at the end...

[Jehan Pagès <jehanp src gnome org>]

commit df8fded8f758c9da090a3cdad48a56aca57597dd
Author: Jehan <jehan girinstud io>
Date:   Tue May 31 01:20:51 2016 +0200

    configure: output the list of missing dependencies at the end...
    
    ... on configuration failure. This makes the failure as well as the list
    of errors more visible.

 configure.ac |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 5942995..d4c4adf 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2551,11 +2551,13 @@ $optional_deps]);
 else
   AC_MSG_ERROR([
 
+== Summary of optional features ==
+$optional_deps
+
+== Missing mandatory dependencies ==
+
 GIMP configuration failed.
 The following mandatory dependencies are missing:$required_deps
 
-See the file 'INSTALL' for more help
-
-== Additional information (options) ==
-$optional_deps]);
+See the file 'INSTALL' for more help.]);
 fi