After making `ffmpeg` point to the latest `ffmpeg_4`, all packages that
used `ffmpeg` without requiring a specific version now use ffmpeg_3
explicitly so they shouldn't change.
* some configure options have been removed upstream
* need a new patch to deal with gcc format warnings
11 remains, as it is an LTS release; all existing users of 11 in
nixpkgs remain on 11 for now.
openjdk/default.nix and openjdk/darwin/default.nix become the
expressions for the current version (12 now; later 13, 14, etc.).
(note: darwin/default.nix was unreferenced; the new version is derived
from darwin/11.nix.)
* increase heap size for building javadoc (this is only needed for the
32-bit build)
* filter out some non-maven jars that crop up in the openjfx build