tools: portaudio4android fork changes headsup

[croissanne]

Currently the prepare-api script checks out the master branch of https://github.com/Gundersanne/portaudio_opensles/. I want to update the default branch further however, so I thought I should give a headsup. I want to finish the https://github.com/Gundersanne/portaudio_opensles/tree/formats branch and make a PR to portaudio itself.

I created https://github.com/Gundersanne/portaudio_opensles/releases/tag/v1 which pins the current 3-years-old version + a recent threading fix. So if the audio in newer apks suddenly breaks after rebuilding with a newer version of portaudio, it might be a good idea to pin it to v1 (and report a bug on my fork). Also it might need autoreconf -fi before configuring or switch to CMake.