[gedit] Add more info in the HACKING file

[Paolo Borelli <pborelli src gnome org>]

commit 05e62bbd5379a392f8ac136424ba621bb1368d58
Author: Paolo Borelli <pborelli gnome org>
Date:   Tue Dec 27 16:56:02 2011 +0100

    Add more info in the HACKING file
    
    Try to address some question raisead on IRC.

 HACKING |   26 ++++++++++++++++++++++++--
 1 files changed, 24 insertions(+), 2 deletions(-)
---
diff --git a/HACKING b/HACKING
index ea70d76..ea0ed9e 100644
--- a/HACKING
+++ b/HACKING
@@ -1,5 +1,5 @@
-guidelines for gedit
-====================
+Source code repository
+======================
 
 gedit source code is maintained using the git version control system
 and is available at the following location:
@@ -14,6 +14,28 @@ A Web Interface is available at:
 
     http://git.gnome.org/cgit/gedit
 
+
+Building from git
+=================
+
+When building from a git checkout you will need to run the
+autogen.sh script which takes care of running automake, autoconf,
+etc and then run "configure" for you. You can pass options like
+--prefix to autogen.sh and they will be forwarded to the configure
+script.
+
+Note that you cannot run gedit from its build directory: you need
+to install it with "make install". For this reason it is highly
+recommended that you install in a separate prefix instead of
+overwriting your system binaries. Note however that when running
+gedit from a custom prefix you will need to set many environment
+variables accordingly, for instance PATH and XDG_DATA_DIR.
+The JHBuild tool can take care of all this for you.
+
+
+Commit guidelines
+=================
+
 Please don't commit directly to the git repository unless
 you have been given the green light to commit freely to gedit. 
 When in doubt assume you haven't ;-).