[PATCH] HACKING: Mention 'guix environment'.

[David Thompson]

Just today I used 'guix environment guix' to quickly create a
development environment for Guix hacking.  I figured it should be
mentioned in the HACKING file to assist developers that happen to
already by using a Guix system.

WDYT?

>From e03345616cd4325cec928d6a6c5f35cbc47eb330 Mon Sep 17 00:00:00 2001
From: David Thompson <address@hidden>
Date: Sun, 23 Nov 2014 08:06:21 -0500
Subject: [PATCH] HACKING: Mention 'guix environment'.

---
 HACKING | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/HACKING b/HACKING
index 0231c7d..ad816aa 100644
--- a/HACKING
+++ b/HACKING
@@ -21,6 +21,12 @@ addition to those mentioned in the installation instructions:
   - [[http://www.gnu.org/software/gettext/][GNU Gettext]]
   - [[http://www.graphviz.org/][Graphviz]]
 
+If you are building Guix on a system that already runs Guix, you can use 'guix
+environment' to spawn a shell whose environment contains all of the necessary
+packages without installing them to your user profile:
+
+  guix environment guix
+
 Run ‘./bootstrap’ to download the Nix daemon source code and to generate the
 build system infrastructure using autoconf.  It reports an error if an
 inappropriate version of the above packages is being used.
-- 
2.1.2

-- 
David Thompson
Web Developer - Free Software Foundation - http://fsf.org
GPG Key: 0FF1D807
Support the FSF: https://fsf.org/donate