liblo: disable werror to fix build issues

Pass the --disable-werror option to remove -Werror, and therefore
avoid a number of build failures.

Fixes:

  http://autobuild.buildroot.net/results/61ab7e23d2ef62f055efc74a998e3c108a3cdb43



Signed-off-by: Alex Baldwin <alexbaldwinmusic@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>