brew doctor

brew doctor

north:src jdumay$ brew doctor

Error: The following libiconv files were detected in /Users/jdumay/software/homebrew:
include/iconv.h
Homebrew doesn't provide a libiconv formula, and expects to link against
the system version in /usr/lib.

If you have an alternate libiconv, many formulae will fail to compile or
link, especially if it wasn't compiled with the proper architectures.
Error: You have unlinked kegs in your Cellar
Leaving kegs unlinked can lead to build-trouble and cause brews that depend on
those kegs to fail to run properly once built.

    node
    ruby
Error: X11 is not installed.
You don't have X11 installed as part of your OS X installation.
This is not required for all formulae, but is expected by some.
You can download the latest version of XQuartz from:
  https://xquartz.macosforge.org
Error: Your Homebrew is not installed to /usr/local
You can install Homebrew anywhere you want, but some brews may only build
correctly if you install in /usr/local. Sorry!