Switch off HAVE_SAVED_UIDS since it activates a code path for temporary
privilege dropping which does not work on NixOS.
Vixie-cron's sources ship with two implementations. Unfortunately, the
one activated by HAVE_SAVED_UIDS (using setuid()) does not work on
NixOS. Saved UIDs work only if the program which is using them has the
setuid bit set on its own executable, not if called from a setuid
wrapper (as we do it in NixOS). The other implementation (using
setreuid()) works without problems.
Quote from
<http://stackoverflow.com/questions/8499296/realuid-saved-uid-effective-uid-whats-going-on>:
If you're euid is root and you change the uid, the privileges gets
dropped permanently.If effective user id is not root then saved user
id is never touched and you can regain the root privilege back
anytime you want in your program.
Also extend the default PATH with NixOS-specific bin directories as
vixie-cron's default is not really usable on NixOS.
Re #16518Closes#16522
From the changelog:
```
Version 0.7.87, 2016-06-30
+ Spanish and catalan languages updated, thanks to Sergi Medina
+ Refactoring of the trace feature, for better performance and some bug fixes
- Visual C++ 2012 project files removed
x Review of symbols display, now using standard display (e.g. "k" instead of "K", " min" instead of "mn"...)
x XML output: revert to old versioning method (version is MediaInfo software version)
x I63, EBUCore/FIMS outputs: typo correction about WritingLibrary and WritingApplication
x Matroska: files with CodecPrivate element before CodecID element where not always correctly parsed
x OGG: crash/incoherent behavior with some buggy OGG streams having invalid chunk sizes
```
Instead of showing this output from "nixos-rebuild switch":
warning: not applying GID change of group ‘munin’
warning: not applying UID change of user ‘ntp’
print this:
warning: not applying GID change of group ‘munin’ (95 -> 102)
warning: not applying UID change of user ‘ntp’ (3 -> 179)
This makes it possible for users to take action and fixup the UIDs/GIDs
that NixOS won't touch.
This update was generated by hackage2nix v20160613-12-g1145e86 using the following inputs:
- Hackage: 53b696d106
- LTS Haskell: 1c63caa7b8
- Stackage Nightly: affdd756e9
