Use Fiddle::Importer directly

Merged: https://github.com/ruby/ruby/pull/3712

ext/win32/lib/win32/importer.rb

@@ -1,9 +0,0 @@
-# frozen_string_literal: false
-require 'fiddle/import'
-
-module Win32
-end
-
-Win32.module_eval do
-  Importer = Fiddle::Importer
-end

ext/win32/lib/win32/registry.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: false
-require 'win32/importer'
+require 'fiddle/import'
 
 module Win32
 
@@ -169,7 +169,7 @@ For detail, see the MSDN[http://msdn.microsoft.com/library/en-us/sysinfo/base/pr
     #
     class Error < ::StandardError
       module Kernel32
-        extend Importer
+        extend Fiddle::Importer
         dlload "kernel32.dll"
       end
       FormatMessageW = Kernel32.extern "int FormatMessageW(int, void *, int, int, void *, int, void *)", :stdcall
@@ -225,7 +225,7 @@ For detail, see the MSDN[http://msdn.microsoft.com/library/en-us/sysinfo/base/pr
     #
     module API
       include Constants
-      extend Importer
+      extend Fiddle::Importer
       dlload "advapi32.dll"
       [
         "long RegOpenKeyExW(void *, void *, long, long, void *)",

ext/win32/lib/win32/sspi.rb

@@ -11,7 +11,7 @@
 # Ruby Distribution License or GNU General Public License.
 #
 
-require 'win32/importer'
+require 'fiddle/import'
 
 # Implements bindings to Win32 SSPI functions, focused on authentication to a proxy server over HTTP.
 module Win32
@@ -36,7 +36,7 @@ module Win32
 
     # Win32 API Functions. Uses Win32API to bind methods to constants contained in class.
     module API
-      extend Importer
+      extend Fiddle::Importer
       dlload "secur32.dll"
       [
         # Can be called with AcquireCredentialsHandleA.call()