Now, if a user is using something like on-target directly, that user
doesn't need to set the DISTRO or TUSER variables if using Ubuntu guests
(so the scripts function the same as they did before Debian guest
support was added).
According to the Debian wiki, installing the package grub installs the
correct version of grub for your suite automatically. This fixes a "you
have held broken packages" error when creating the package manifest due
to a conflict between grub-pc and grub-legacy (at least with Wheezy).
Check for older suites with 686 flavour before checking for 686-pae
flavour suites, because the former should never change, but the latter
would have to be changed whenever a new suite was released if it wasn't
the last if statement.
It seems like a lsb_release program should be available on any distro if
the appropriate package is installed. So it seems better to use
lsb_release instead of /etc/lsb-release, because Debian doesn't appear
to have /etc/lsb-release.
The build process for [Bitcoin](https://github.com/bitcoin/bitcoin/blob/master/doc/gitian-building.md) was failing with the following error
```
./bin/gbuild:21:in `system!': failed to run on-target setarch x86_64 bash -x < var/build-script > var/build.log 2>&1 (RuntimeError)
from ./bin/gbuild:137:in `build_one_configuration'
from ./bin/gbuild:267:in `block (2 levels) in <main>'
from ./bin/gbuild:262:in `each'
from ./bin/gbuild:262:in `block in <main>'
from ./bin/gbuild:260:in `each'
from ./bin/gbuild:260:in `<main>'
```
Inside the log file `var/build.log` the entries towards the end show
```
/bin/sh: 1: wget: not found
```
Added info for OS X homebrew commands alongside the Macports as some people prefer to use Homebrew over MacPorts and it is a pain to switch over from the two.
This should allow anyone to write any signing program and use it in
conjunction with gsign as long as it supports the same options/arguments
as gpg does (namely -u for the signer and an argument for the file to
sign).
