libdvdnav runs dvdread-config to update CFLAGS and LDFLAGS with libdirs, includirs and libraries but wrongly with locations on the buildsystem. this breaks crosscompiling. We fix this with providing a own 'dvdread-config' file which dont inject /usr/include and /usr/lib in our *CFLAGS.
Merge pull request #3198 from sraue/dvdread-config-fix

libdvdnav runs dvdread-config to update CFLAGS and LDFLAGS with libdirs,...