therubyracer installation on windows with libv8 installed --with-system-v8 - ruby

Question

I finally got libv8 installed on my windows with
gem install libv8 -- --with-system-v8
now when I am trying to install therubyracer I get
gem install therubyracer
Temporarily enhancing PATH to include DevKit...
Building native extensions. This could take a while...
Building native extensions. This could take a while...
ERROR: Error installing therubyracer:
ERROR: Failed to build gem native extension.
C:/Ruby193/bin/ruby.exe extconf.rb --with-system-v8
checking for main() in -lpthread... no
checking for v8.h... no
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers. Check the mkmf.log file for more
details. You may need configuration options.
Provided configuration options:
--with-opt-dir
--without-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=C:/Ruby193/bin/ruby
--with-pthreadlib
--without-pthreadlib
--enable-debug
--disable-debug
--with-v8-dir
--without-v8-dir
--with-v8-include
--without-v8-include=${v8-dir}/include
--with-v8-lib
--without-v8-lib=${v8-dir}/
C:/Ruby193/lib/ruby/gems/1.9.1/gems/libv8-3.16.14.3/ext/libv8/location.rb:50:in `configure': You hav
e chosen to use the version of V8 found on your system (Libv8::Location::System::NotFoundError)
and *not* the one that is bundle with the libv8 rubygem. However,
it could not be located. please make sure you have a version of
v8 that is compatible with 3.16.14.3 installed. You may
need to special --with-v8-dir options if it is in a non-standard
location
thanks,
The Mgmt
What I want to know is what this error message really means?
Also I looked this up https://github.com/cowboyd/libv8#bring-your-own-v8
How do I install headers for v8?

Answer 1

When I faced this problem I found that I didn't need those gems in development, because rails use to precompile your assets, so my solution was pretty simple,
Gemfile
gem "rails"
group :production do
gem 'therubyracer'
end
Then when you bundle run this command
$ bundle install --without production
Then smile to the life :D

Answer 2

On Mac you can try updating the v8 library with homebrew:
gem uninstall libv8
brew install v8
gem install therubyracer
Update: Sorry, didn't realize this was a Windows only question.

Answer 3

#Aalap
I ran into the same problem while setting up my Ruby on Rails web application on Windows 7 64-bit. I came across this solution. This is a bit old but solved the problem. This solution provides 'therubyracer' gem file and v8.dll libs to install. The instructions are pretty much clear on the link above.
I installed 'libv8' gem just like Periback's answer on SO and when I tried to install 'therubyracer' gem, it failed with same error as yours. Now my web application is running fine and my "gem list" command shows:
libv8 (3.11.8.13)
therubyracer (0.11.0beta1 x86-mingw32)
Hope this helps.