Option 0: The new, under-development installer script:

    $ curl http://rosuav.github.io/Gypsum/get_gypsum_osx.sh | /bin/bash

The best way to install Gypsum on OS X is to use Homebrew (http://brew.sh/).
First, install XQuartz from https://www.xquartz.org/ and Homebrew (if you don't
already have it). Due to differences in license terms, you have to explicitly
install each of these. Then install Pike.

Option 1: Open a Terminal and type:

    $ echo 'WAIT! Did you read the paragraph at the top of this file?'
    $ echo 'Go back and read that first. And do it. Thanks!'
    $ brew install pike
    $ pike -e GTK2.setup_gtk

The second command should produce no output. If it says that setup_gtk is not
present in module GTK, try other installation options.

Option 2: In the terminal, type:

    $ brew uninstall pike
    $ brew install --build-from-source pike
    $ pike -e GTK2.setup_gtk

Again, if this produces an error, try option 3:

    $ brew uninstall pike
    $ curl -O https://dl.dropboxusercontent.com/s/a0xun5ygg6zavqa/pike.tgz
    $ sudo tar xf pike.tgz -C /
    $ pike -e GTK2.setup_gtk

The tar command may spew error messages. I still haven't pinned down exactly
why, but El Capitan seems to be different from Mavericks in this. It may or may
not have succeeded.

Finally, install and run Gypsum:

    $ curl -OL https://github.com/Rosuav/Gypsum/archive/master.zip
    $ unzip master.zip
    $ cd gypsum-master
    $ pike gypsum

Creating a shortcut/program/application to do the "pike gypsum" at the end is
left as an exercise for the reader :)
