doc/README

rust-cpython: fix build for MacOSX

MacOSX needs special link flags. Quoting the README of rust-cpython:

  create a `.cargo/config` with the following content:

  ```
  [target.x86_64-apple-darwin]
  rustflags = [
    "-C", "link-arg=-undefined",
    "-C", "link-arg=dynamic_lookup",
  ]
  ```

This is tested with Python 2.7 (Anaconda install) and Python 3
(Homebrew install)

Mercurial's documentation is kept in reStructuredText format, which is
a simple plain text format that's easy to read and edit:

  http://docutils.sourceforge.net/rst.html

It's also convertible to a variety of other formats including standard
UNIX man page format and HTML. You'll need to install Docutils:

  http://docutils.sourceforge.net/

Use the Makefile in this directory to generate the man and HTML pages.