buildroot

package/x11r7/xapp_xf86dga: remove dependencies on Xt/Xaw/Xmu

Fixes:
http://autobuild.buildroot.net/results/aee/aee4a895c74647292715705bfcdf742f3ea2f76f/

Since the bump to 1.0.3, xapp_xf86dga no longer uses libXt, libXaw and
libXmu. So these dependencies should be removed from the .mk file.

They were already removed from Config.in, leading to messages like:
Makefile:475: *** xlib_libXaw is in the dependency chain of xapp_xf86dga
that has added it to its _DEPENDENCIES variable without selecting it or
depending on it from Config.in.  Stop.

[Peter: add autobuilder reference as suggested by Ricardo]
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Cc: Bernd Kuhls <bernd.kuhls@t-online.de>
Cc: Ricardo Martincoski <ricardo.martincoski@gmail.com>
Tested-by: Ricardo Martincoski <ricardo.martincoski@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>