Do not introduce indeterminism when compressing initrd.
Fix non-deterministic id-generation for the nixos-manual.
Make python 2.7 deterministic.

Unfortunately this kills the wininst feature as I could
not figure out how to get the .exe files deterministic.
Make apr-util deterministic.
Make the system tarball deterministic.
Do not link with rt to avoid duplicate definition error.

This was apparently something others have seen as well:
https://github.com/wolfcw/libfaketime/blob/master/packaging/Linux/Debian/avoid-spurious-lrt.patch
Not patching elf binaries result in non-deterministic builds.

I have no idea why dontPatchELF was set.  If it was not important enough to comment
on it might have been a spurious issue.
Fix date in version string.

ntp cannot be safely built with useFakeTime because
the version construction system detects how many
times the version string is constructed, and it can
be constructed more than once when the time is
fixed by libfaketime.
Make smartmontools deterministic.
Set useFakeTime on a set of derivations.

This might not be the best of ideas as this can cause
build problems.
However, it makes the build deterministic for now.