[Nix-dev] Defining env vars for user .nix-profile ?

[Marc Weber]

How is this done?

Gentoo has /etc/env.d/ which looks like this

/etc/env.d/
/etc/env.d/gcc
/etc/env.d/gcc/avr-3.4.6-hardenednopie
/etc/env.d/gcc/avr-3.4.6-hardenednossp
/etc/env.d/gcc/avr-3.4.6
/etc/env.d/gcc/avr-3.4.6-hardened
/etc/env.d/gcc/i686-pc-linux-gnu-4.1.1
/etc/env.d/05gcc
/etc/env.d/08nss
/etc/env.d/20ant
[...]

each is a sh file defining/appending values to env variables.

I'm asking because I'm using one ghc pkg database file for each library.
They all have to be put in a ':' or ';' (Win) separated list
$GHC_PACKAGE_PATH to be
accsible.

How is this handled in nix?
a) automatically? (thus using something like the gentoo system)
b) requires user action (eg sourcing a script in his .bashrc ) ?

Marc