This example shows proper timing and A/V synchronization with an OpenAL stream.
Requires the in-progress AL_SOFTX_source_length extension to avoid manually
keeping track of the buffer queue length.
This should make it easier to build the examples on 64-bit, where there are no
premade dev libs for SDL1 on 64-bit mingw. FindSDL_sound.cmake has been
updated to accept SDL or SDL2.
Some (all?) versions of cmake seem to get a bit confused when an old-style
FIND_PACKAGE_HANDLE_STANDARD_ARGS call fails, and the scripts attempt a new-
style call later on. It continues to think it's using old-style, acting as if
REQUIRED_VARS is the message and looks for a VERSION_VAR variable.
