Citation :=> Booting WEBrick
=> Rails 3.0.0 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
[2010-09-01 10:04:27] INFO WEBrick 1.3.1
[2010-09-01 10:04:27] INFO ruby 1.9.2 (2010-08-18) [i386-mingw32]
[2010-09-01 10:04:27] INFO WEBrick::HTTPServer#start: pid=5556 port=3000

Citation :Building native extensions. This could take a while...
ERROR: Error installing unicorn:
ERROR: Failed to build gem native extension.

C:/Ruby192/bin/ruby.exe extconf.rb
checking for SIZEOF_OFF_T in ruby.h... *** 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:/Ruby192/bin/ruby
--with-unicorn_http-dir
--without-unicorn_http-dir
--with-unicorn_http-include
--without-unicorn_http-include=${unicorn_http-dir}/include
--with-unicorn_http-lib
--without-unicorn_http-lib=${unicorn_http-dir}/lib
C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:368:in `try_do': The complier failed to generate an executable fil
e. (RuntimeError)
You have to install development tools first.
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:446:in `try_compile'
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:605:in `macro_defined?'
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:725:in `block in have_macro'
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:693:in `block in checking_for'
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:280:in `block (2 levels) in postpone'
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:254:in `open'
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:280:in `block in postpone'
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:254:in `open'
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:276:in `postpone'
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:692:in `checking_for'
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:724:in `have_macro'
from extconf.rb:6:in `<main>'


Gem files will remain installed in C:/Ruby192/lib/ruby/gems/1.9.1/gems/unicorn-1.1.3 for inspection.

Results logged to C:/Ruby192/lib/ruby/gems/1.9.1/gems/unicorn-1.1.3/ext/unicorn_http/gem_make.out

Citation :source 'http://rubygems.org'

gem 'rails', '3.0.0'
gem 'mysql'
gem 'gravatar_image_tag'

group :development do
gem 'rspec-rails'
gem 'annotate-models', '1.0.4'
end

group :test do
gem 'rspec'
end