applyAndFun has a bug resulting in the same arg beeing added more than
once when using a concatenating merge function for the attr set.
I've tried giving the function a name "overridableDelayableArgs" which
resembles its usage much more.
important refactoring:
applyAndFun had .fun and .funMerge only when passing the merge
function lib.mergeOrApply
composableDerivation {
initial = {
...
};
}
to
overridableDelayableArgs has always .replace and .merge
composableDerivation {} {
...
}
svn path=/nixpkgs/trunk/; revision=14428
