libroxml: fix avr32 build failure

The -Wno-unused-result option is not understood by the version of gcc used by the
avr32 toolchain. Remove the option from the compilation flags.

Fixes build failures such as the following.

  http://autobuild.buildroot.net/results/e22/e22d94fca3eabb4e54d82af04319f17ad8e10c20/



The single existing patch for libroxml has been renamed to include a numerical
component for application order sorting. The existing patch has also been updated
to apply without fuzz.

Signed-off-by: Simon Dawson <spdawson@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>