Nix configuration directory for the MMGen Wallet suite

NOTE: If you plan to make changes to the files in this directory, first copy it
(e.g. `cp -a nix mynix`) and then make your changes in the copied directory.
Also make sure to replace ‘nix’ with ‘mynix’ (e.g.) in the examples below.

Only BTC and a bare minimum of packages are enabled by default.

For altcoin and additional package support, copy the file ‘user-packages.nix’ to
your MMGen datadir (~/.mmgen) and edit, uncommenting the relevant lines.  For an
XMR-enabled setup, for example, you’d uncomment the system package ‘monero-cli’
and Python packages ‘monero’, ‘pycryptodome’ and ‘pysocks’.

From the mmgen-wallet repo root, you may build individual system packages in the
MMGen Wallet environment as follows (we’ll use the curl package in this example):

   $ nix-build nix --attr curl

To build all configured packages in one go, run ‘nix-build nix’ without
additional arguments.

The last lines of nix-build’s output are store paths in ‘/nix/store/’, which
you may optionally install into your default environment as follows:

   $ nix-env --install <store path>

Note that use of MMGen Wallet from the default environment is discouraged in
favor of the custom shell environment, which we’ll now describe.

From the mmgen-wallet repo root, execute:

   $ nix-shell nix

This will build any unbuilt configured packages and drop you to the custom shell
environment.  At this point you may run the test suite:

   [nix-shell:... $] test/test-release -FA

or proceed to use MMGen Wallet as with any conventional installation.

For greater isolation, you can invoke nix-shell with the ‘--pure’ option. This
will make executables from your native environment inaccessible within the
shell, so you may need to add some additional tools to your environment such as
a text editor.  For examples, refer to ‘user-packages.nix’

Speedup tip: Look for the commented-out ‘url =’ lines in the *.nix files in
this directory, and make local shallow clones of the corresponding remote git
repositories using ‘git clone --depth=1’ plus ‘--revision=<commit>’ or
‘--branch=<tag>’.  Then uncomment the local paths, adjusting them to suit.
This will also allow you to use your installation in an offline environment.

NixOS:

  To install the MMGen Wallet environment under NixOS, copy the contents of the ‘nix’
  directory to ‘/etc/nixos/mmgen-project’ and add ‘./mmgen-project/nixos-packages.nix’
  to your imports list in ‘configuration.nix’.  If altcoin support or additional
  packages are required, edit ‘user-packages.nix’ in ‘/etc/nixos/mmgen-project’ as
  described above for the copy of that file in the MMGen datadir.  Rebuild NixOS.
  From the mmgen-wallet repo root, execute:

      export PYTHONPATH=$(pwd)
      export PATH=$(pwd)/cmds:$PATH

  You can now test and use MMGen Wallet in your native shell environment.
