Quick hack from mysql gem.

Added vendored MySQL.

.gitignore

@@ -7,3 +7,5 @@ Makefile
 *.rbc
 mkmf.log
 pkg/
+tmp
+vendor

Rakefile

@@ -20,8 +20,6 @@ end
 
 require 'rake'
 require 'spec/rake/spectask'
-gem 'rake-compiler', '~> 0.7.1'
-require "rake/extensiontask"
 
 desc "Run all examples with RCov"
 Spec::Rake::SpecTask.new('spec:rcov') do |t|
@@ -36,7 +34,5 @@ Spec::Rake::SpecTask.new('spec') do |t|
   t.spec_opts << '--options' << 'spec/spec.opts'
 end
 
-Rake::ExtensionTask.new("mysql2", JEWELER.gemspec) do |ext|
-  ext.lib_dir = File.join 'lib', 'mysql2'
-end
-Rake::Task[:spec].prerequisites << :compile
+# Load custom tasks
+Dir['tasks/*.rake'].sort.each { |f| load f }

tasks/compile.rake

@@ -0,0 +1,19 @@
+gem 'rake-compiler', '~> 0.7.1'
+require "rake/extensiontask"
+
+MYSQL_VERSION = "5.1.49"
+MYSQL_MIRROR  = ENV['MYSQL_MIRROR'] || "http://mysql.localhost.net.ar"
+
+Rake::ExtensionTask.new("mysql2", JEWELER.gemspec) do |ext|
+  # reference where the vendored MySQL got extracted
+  mysql_lib = File.expand_path(File.join(File.dirname(__FILE__), '..', 'vendor', "mysql-#{MYSQL_VERSION}-win32"))
+
+  # automatically add build options to avoid need of manual input
+  if RUBY_PLATFORM =~ /mswin|mingw/ then
+    ext.config_options << "--with-mysql-include=#{mysql_lib}/include"
+    ext.config_options << "--with-mysql-lib=#{mysql_lib}/lib/opt"
+  end
+
+  ext.lib_dir = File.join 'lib', 'mysql2'
+end
+Rake::Task[:spec].prerequisites << :compile

tasks/vendor_mysql.rake

@@ -0,0 +1,41 @@
+require 'rake/clean'
+require 'rake/extensioncompiler'
+
+# download mysql library and headers
+directory "vendor"
+
+file "vendor/mysql-noinstall-#{MYSQL_VERSION}-win32.zip" => ['vendor'] do |t|
+  base_version = MYSQL_VERSION.gsub(/\.[0-9]+$/, '')
+  url = "http://dev.mysql.com/get/Downloads/MySQL-#{base_version}/#{File.basename(t.name)}/from/#{MYSQL_MIRROR}/"
+  when_writing "downloading #{t.name}" do
+    cd File.dirname(t.name) do
+      sh "wget -c #{url} || curl -C - -O #{url}"
+    end
+  end
+end
+
+file "vendor/mysql-#{MYSQL_VERSION}-win32/include/mysql.h" => ["vendor/mysql-noinstall-#{MYSQL_VERSION}-win32.zip"] do |t|
+  full_file = File.expand_path(t.prerequisites.last)
+  when_writing "creating #{t.name}" do
+    cd "vendor" do
+      sh "unzip #{full_file} mysql-#{MYSQL_VERSION}-win32/bin/** mysql-#{MYSQL_VERSION}-win32/include/** mysql-#{MYSQL_VERSION}-win32/lib/**"
+    end
+    # update file timestamp to avoid Rake perform this extraction again.
+    touch t.name
+  end
+end
+
+# clobber expanded packages
+CLOBBER.include("vendor/mysql-#{MYSQL_VERSION}-win32")
+
+# vendor:mysql
+task 'vendor:mysql' => ["vendor/mysql-#{MYSQL_VERSION}-win32/include/mysql.h"]
+
+# hook into cross compilation vendored mysql dependency
+if RUBY_PLATFORM =~ /mingw|mswin/ then
+  Rake::Task['compile'].prerequisites.unshift 'vendor:mysql'
+else
+  if Rake::Task.tasks.map {|t| t.name }.include? 'cross'
+    Rake::Task['cross'].prerequisites.unshift 'vendor:mysql'
+  end
+end