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
(My OCD kicked in today...)
Remove repeated package names, capitalize first word, remove trailing
periods and move overlong descriptions to longDescription.
I also simplified some descriptions as well, when they were particularly
long or technical, often based on Arch Linux' package descriptions.
I've tried to stay away from generated expressions (and I think I
succeeded).
Some specifics worth mentioning:
* cron, has "Vixie Cron" in its description. The "Vixie" part is not
mentioned anywhere else. I kept it in a parenthesis at the end of the
description.
* ctags description started with "Exuberant Ctags ...", and the
"exuberant" part is not mentioned elsewhere. Kept it in a parenthesis
at the end of description.
* nix has the description "The Nix Deployment System". Since that
doesn't really say much what it is/does (especially after removing
the package name!), I changed that to "Powerful package manager that
makes package management reliable and reproducible" (borrowed from
nixos.org).
* Tons of "GNU Foo, Foo is a [the important bits]" descriptions
is changed to just [the important bits]. If the package name doesn't
contain GNU I don't think it's needed to say it in the description
either.
