Including MailCore for RubyMotion project.

Rakefile

# -*- coding: utf-8 -*-
$:.unshift("/Library/RubyMotion/lib")
require 'motion/project'

Motion::Project::App.setup do |app|
  # Use `rake config' to see complete project settings.
  app.name = 'HelloMailCore'

  # Configure MailCore
  app.vendor_project("vendor/MailCore", :xcode, :headers_dir => "{../include,libetpan/build-mac/.build/include/libetpan}", :target => "MailCore iOS")
  app.frameworks << "CFNetwork"
  app.libs << "/usr/lib/libiconv.dylib"
  app.libs << "vendor/MailCore/iOSPorts/ports/security/cyrus-sasl/.build/libsasl2.a"
  app.libs << "vendor/MailCore/iOSPorts/ports/security/openssl/.build/libcrypto.a"
  app.libs << "vendor/MailCore/iOSPorts/ports/security/openssl/.build/libssl.a"
end

Steps I took, from RubyMotion project directory:

rake clean
git clone --recursive git://github.com/mronge/MailCore.git vendor/MailCore
rake