include/libac.h: Mark functions as extern
include/libac.h: Mark functions as extern

Yes, this is the default and you don't normally mark them extern in the
.c files but often do in the .h files, so...

Signed-off-by: Andrew Clayton <02e0a999c50b1f88df7a8f5a04e1b76b35ea6a88@digital-domain.net>

ac000/libac