[gtkglext] Add AM_CONDITIONAL(GLU).

[Ralf Corsépius <rcorsepius src gnome org>]

commit 8c88d5ab4008c02608422d26c8ef6b65a4727081
Author: Ralf Corsepius <rcorsepius src gnome org>
Date:   Wed Dec 30 05:27:59 2009 +0100

    Add AM_CONDITIONAL(GLU).

 configure.ac |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 96516e1..c0b895d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -243,6 +243,8 @@ PKG_CHECK_MODULES([PANGOFT2], [pangoft2], ,
                          [AC_MSG_WARN([Pango Freetype support is required to build some of the examples.])])])
 
 AX_CHECK_GLU
+# FIXME: AX_CHECK_GLU's behavior diverges from common autoconf conventions
+AM_CONDITIONAL([GLU],[test "$no_glu" != yes])
 
 # Checks for some types in gdk/GL/glxext.h