virtualbox: Comply with the Personal Use and Evaluation License

[bbenoist]

The direct download was unfortunately not compliant with the VirtualBox
Extension Pack's Personal Use and Evaluation License (PUEL) which
stipulates that any end-user should fetch the binaries from the official
Downloads page.

See #672 for the original issue and
http://www.virtualbox.org/wiki/VirtualBox_PUEL for more info.

[domenkozar]

Can we get rid of extpackRevision?

[vcunat]

@iElectric: I tried that but @bbenoist (I think) presented some good reasons, not sure what they were now.

[domenkozar]

Any further objections?

[bjornfor]

@bbenoist: Merged manually. I had to move extpackRevision out of the requireFile call, because of this:

$ nix-build -A linuxPackages.virtualbox
error: `requireFile' at `/home/bfo/nixpkgs/pkgs/build-support/trivial-builders.nix:85:17' called with unexpected argument `extpackRevision'

It's a bit funny, now that Oracle has put out new releases, the version we require isn't listed anymore directly in the "Downloads" page. You have to scroll down and click on "VirtualBox older builds", then click on the "4.2" link and then click on the final link :-)

Go here to find it: https://www.virtualbox.org/wiki/Download_Old_Builds_4_2

[bbenoist]

@bjornfor I cannot figure out why this error did not occurred when I rebuilt it, I may have been distracted 😕 Thank you for your correction and merge.
About the "older builds" page, this is one logical consequence of relying on a main download page: new versions are released on it before being integrated on distributions. Even stable distros would suffer of it if no new version is released before their integration.

Oracle seems to be focusing on virtualbox now ( http://www.zdnet.com/oracle-to-halt-development-of-sun-virtualization-technologies-7000018028/ ), we can expect some evolution (positive or not) as this painful web browsing step is even required for Windows binaries.