Attempt to enable static linking for Windows

ext/mysql2/extconf.rb

@@ -26,7 +26,8 @@ GLOB = "{#{dirs.join(',')}}/{mysql_config,mysql_config5}"
 
 if RUBY_PLATFORM =~ /mswin|mingw/
   inc, lib = dir_config('mysql')
-  exit 1 unless have_library("libmysql")
+  library = enable_config('static') ? 'mysqlclient' : 'libmysql'
+  exit 1 unless have_library(library)
 elsif mc = (with_config('mysql-config') || Dir[GLOB].first) then
   mc = Dir[GLOB].first if mc == true
   cflags = `#{mc} --cflags`.chomp

tasks/compile.rake

@@ -15,7 +15,8 @@ Rake::ExtensionTask.new("mysql2", gemspec) do |ext|
   # DRY options feed into compile or cross-compile process
   windows_options = [
     "--with-mysql-include=#{mysql_lib}/include",
-    "--with-mysql-lib=#{mysql_lib}/lib/opt"
+    "--with-mysql-lib=#{mysql_lib}/lib/opt",
+    '--enable-static'
   ]
 
   # automatically add build options to avoid need of manual input