Remove remaining rake use

Author: kateinoigakukun

lib/ruby_wasm/build_system.rb

@@ -1,4 +1,3 @@
-require "rake"
 require_relative "build_system/build_params"
 require_relative "build_system/product"
 require_relative "build_system/toolchain"

lib/ruby_wasm/build_system/product.rb

@@ -1,4 +1,3 @@
-require "rake"
 require_relative "product/product"
 require_relative "product/ruby_source"
 require_relative "product/baseruby"

lib/ruby_wasm/build_system/product/crossruby.rb

@@ -123,7 +123,7 @@ def configure(reconfigure: false)
 
     def build_exts
       @user_exts.each { |prod| prod.build(self) }
-      mkdir_p File.dirname(extinit_obj)
+      FileUtils.mkdir_p File.dirname(extinit_obj)
       system %Q(ruby #{extinit_c_erb} #{@user_exts.map(&:name).join(" ")} | #{toolchain.cc} -c -x c - -o #{extinit_obj})
     end
 

lib/ruby_wasm/build_system/product/product.rb

@@ -1,9 +1,5 @@
-require "rake"
-
 module RubyWasm
   class BuildProduct
-    include Rake::DSL
-
     def name
       raise NotImplementedError, "identifiable product name must be implemented"
     end