[gcompris] minor: added a message in the configure to define the GNUCHESS environment variable.

[Bruno Coudoin <bcoudoin src gnome org>]

commit 330cc4785d6b0373f853c8fe608b34951dc22b2b
Author: Bruno Coudoin <bruno coudoin free fr>
Date:   Thu May 17 21:06:40 2012 +0200

    minor: added a message in the configure to define the GNUCHESS environment variable.

 configure.ac |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index fccc9f0..0ea136b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -361,7 +361,8 @@ else
   dnl Test for gnuchess
   AC_PATH_PROGS(GNUCHESS, gnuchess gnome-gnuchess, no, [/usr/bin:/usr/games:/usr/local/bin:$PATH])
   if test x$GNUCHESS = xno; then
-    AC_MSG_ERROR(Couldn't find gnuchess, please install the gnuchess package version 5 or above)
+    AC_MSG_ERROR([Couldn't find gnuchess, please install the gnuchess package version]
+                 [ 5 or above or define the environment variable GNUCHESS.])
   fi
   AC_DEFINE_UNQUOTED(GNUCHESS, "$GNUCHESS", Defines where GNU Chess resides on the system)
   build_gnuchess=no