Small style fixups

In this commit, I modified some files, conforming them to a
idiosyncratic standard - mainly, a template for meta attribs.
IntelliJ IDEA: do not assume that we are using OpenJDK.
add functor-infix
Merge pull request #4046 from phunehehe/add-functor-infix

add functor-infix
Merge pull request #4030 from AndersonTorres/small-fixups

Small style fixups
nixos/ssh: Allow user to configure the package that provides ssh/sshd
Fix typo in meta
Merge pull request #4036 from lostdj/ltp/master/ijifix

IntelliJ IDEA: do not assume that we are using OpenJDK.
readline-6.3: Fix building on Darwin

The zip file contains files named CHANGELOG and ChangeLog, so the
build fails on case-insensitive systems with:

  error: creating file `/nix/store/nix-4888-0/unpacked/ChangeLog': File exists

The official tar distribution does not have this problem.
readline: Name Nix expressions consistently
Doh
R: update to version 3.1.1
nixos/jekins: add services.jenkins.extraGroups option

This makes it easy to give jenkins extra privileges by adding group
memberships. Use with care :-)
fix vaapiVdpau build with patch
Add MuseScore 1.3.
sbt: drop unconditionally set $SBT_OPTS variable from script

... and rename simple-build-tool to just "sbt", which is the name
everybody uses these days.
directfb: Update to 1.7.6
Merge pull request #4049 from vandenoever/musescore

Add MuseScore 1.3.
Merge pull request #4055 from linquize/directfb

directfb: Update to 1.7.6
Merge pull request #4053 from matejc/fix_vaapivdpau

fix vaapiVdpau build with patch