[gtk+/gtk-3-4] ./configure: fix error output for no -libXext

[Matthias Clasen <matthiasc src gnome org>]

commit 336575a1499b76d9de55e9f32741e4e013f2214e
Author: Ryan Lortie <desrt desrt ca>
Date:   Mon Apr 16 09:34:30 2012 -0400

    ./configure: fix error output for no -libXext
    
    Due to the way the tests are structured, a missing libXext will give a
    warning about a missing libX11 (even if libX11 is installed).  This is
    confusing to people who are trying to build Gtk.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=674200

 configure.ac |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 95d0955..af5c3f8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -961,9 +961,9 @@ if test "x$enable_x11_backend" = xyes; then
   # Xext is optional, the chances a system has *none* of these things is so
   # small that we just unconditionally require it.
   AC_CHECK_FUNC(XOpenDisplay, :,
-                AC_MSG_ERROR([*** libX11 not found. Check 'config.log' for more details.]))
+                AC_MSG_ERROR([*** libX11 and libXext not found. Check 'config.log' for more details.]))
   AC_CHECK_FUNC(XextFindDisplay, :,
-                AC_MSG_ERROR([*** libXext not found. Check 'config.log' for more details.]))
+                AC_MSG_ERROR([*** libX11 and libXext not found. Check 'config.log' for more details.]))
 
   # Check for xReply