The function strtok_r() is part of the POSIX.1 specification, but is not
available on some platforms. We provide an internal implementation, so we
do not need to rely on a platform implementation.
A function name should tell what the function does rather than what
the function returns. This also avoids possible conflicts
(e.g. between a function and a public list of all supported formats),
and clarifies the code.
Breaks audio API/ABI, add a backward compatibility layer for video
API/ABI.