Ancient config.guess fails to work on 64-bit MIPS platforms
The 'config.guess' file that you distribute with your most recent libtheora tarballs (including 1.2.0alpha1) is from 2003. It fails to work properly on 64-bit MIPS systems such as Loongson.
As it says in the comments of any recent 'config.guess' (e.g. from a recent GCC release):
You can get the latest version of this script from: http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.guess;hb=HEAD