Comment 75 for bug 602934

Created an attachment (id=139)
Yet another patch...

Okay, this one should allow building again the FFmpeg HEAD headers. The last
couple of patches allowed Audacity to use FFmpeg HEAD libraries, but not build
against the headers. I'd left out a bit of Benjamin's original patch...

This also prevents errors appearing in the log when (optional) symbols are not
found. It will now only display errors when a true error occurs during symbol
lookup.

In addition, it doesn't add track number and year metadata during import when
there isn't any.

All "deprecated" messages should be gone as well...as of today.

Remember, ffmpeg sources are very much in flux so what builds today may not
build tomorrow.