Find location of installed package in /gnu/store

[Phil Beadling]

Hi,

Given a package definition, eg icedtea-8's JDK, how can can I determine the
location of the installed package in my /gnu/store?

There doesn't seem to be anything on the package module itself, presumably
because this is static data, and what I need is something to calculate the
hash of the resulting install specific to my Guix?

eg
scheme@(guix-user) [3]> (package-outputs icedtea-8)
$8 = ("out" "jdk" "doc")
scheme@(guix-user) [3]>

I'd like to return this location using the package name or definition as an
input:
/gnu/store/i3vf1a49m0abcjqza19mb4mkjmc6k60n-icedtea-3.7.0-jdk/

The aim is to use this to derivive the JDK include directories in a generic
way for some scripts I'm writing, such that I don't need to update them
each time the JDK hash changes after a guix pull.

Cheers,
Phil.