This will probably be mandatory soon, and is a step in the right
direction. Removes the deprecated meta.version, and move some meta
sections to the end of the file where I should have put them in
the first place.
An interesting thing is that: stdenv != overrideCC stdenv gcc49;
I'm not sure why that is, but it doesn't seem important.
/cc maintainers: @nckx, @garbas, @abbradar, @cstrahan, @grwlf.
(cherry picked from commit 3064b6a0cc)
