libao plugins call functions defined in libao proper

Our project uses libltdl to dynamically load plugin modules. One of our modules links against libao. When we try to load that module, libao prints an error message stating that dlopen() failed when loading libao's alsa plugin. I patched libao, so that I could see the message reported by dlerror. dlerror claims that ao_is_big_endian is undefined. Should libao's plugins be calling functions defined by libao itself?

Note that this also causes problems for language bindings like pyao.