diff --git a/.gitignore b/.gitignore
index 9202c44..7ae9af4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,6 +2,7 @@
 *.bundle
 *.so
 *.a
+.rbx/
 Gemfile.lock
 pkg/*
 tmp/*
diff --git a/Rakefile b/Rakefile
index 9058436..45df8bc 100644
--- a/Rakefile
+++ b/Rakefile
@@ -15,7 +15,7 @@ task :checkout do
   sh "git submodule update --init"
   Dir.chdir(V8_Source) do
     sh "git fetch"
-    sh "git checkout #{V8_Version}"
+    sh "git checkout #{V8_Version} -f"
     sh "#{make} dependencies"
   end
 end
@@ -31,7 +31,7 @@ task :manual_compile do
   require File.expand_path '../ext/libv8/arch.rb', __FILE__
   include Libv8::Arch
   Dir.chdir(V8_Source) do
-    sh "#{make} -j2 #{libv8_arch}.release"
+    sh %Q{#{make} -j2 #{libv8_arch}.release GYPFLAGS="-Dhost_arch=#{libv8_arch}"}
   end
 end
 
@@ -58,4 +58,4 @@ task :clean do
 end
 
 task :default => [:checkout, :compile, :spec]
-task :build => :checkout
\ No newline at end of file
+task :build => [:clean, :checkout]
diff --git a/ext/libv8/extconf.rb b/ext/libv8/extconf.rb
index 92716d0..4822f5e 100644
--- a/ext/libv8/extconf.rb
+++ b/ext/libv8/extconf.rb
@@ -7,5 +7,5 @@ include Libv8::Arch
 include Libv8::Make
 
 Dir.chdir(File.expand_path '../../../vendor/v8', __FILE__) do
-  puts `#{make} #{libv8_arch}.release`
+  puts `#{make} #{libv8_arch}.release GYPFLAGS="-Dhost_arch=#{libv8_arch}"`
 end