In #177410 `SASL_PATH` was set for kdepim-runtime binaries to allow usage of plugin for XOAUTH2, which is required for some mail servers like Gmail. Unfortunately in that PR wrong output of cyrus_sasl was chosen, fixing it in this PR.
Nix expressions provide all the features that Quilt series files have,
so using those instead is pointless. Also, lib.readPathsFromFile
(the function used to read series files) has the following warning:
> NOTE: This function is not performant and should be avoided.
This also removes some orphaned series files, and unused references to
copyPathsToStore (which were probably missed in previous commits
where calls to lib.readPathsFromFile were removed)
