こんにちは、watir をインストールしようとしています。Ruby をインストールし、RubyGem マネージャーを更新しました。watir (Windows 8 64bit) をインストールしようとすると、次のようになります。
C:\devkit>gem install watir
Temporarily enhancing PATH to include DevKit...
Building native extensions. This could take a while...
ERROR: Error installing watir:
ERROR: Failed to build gem native extension.
C:/Ruby200-x64/bin/ruby.exe extconf.rb
checking for ffi.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:/Ruby200-x64/bin/ruby
--with-ffi_c-dir
--without-ffi_c-dir
--with-ffi_c-include
--without-ffi_c-include=${ffi_c-dir}/include
--with-ffi_c-lib
--without-ffi_c-lib=${ffi_c-dir}/
--with-libffi-config
--without-libffi-config
--with-pkg-config
--without-pkg-config
C:/Ruby200-x64/lib/ruby/2.0.0/mkmf.rb:431:in `try_do': The compiler failed to generate an executable
file. (RuntimeError)
You have to install development tools first.
from C:/Ruby200-x64/lib/ruby/2.0.0/mkmf.rb:562:in `try_cpp'
from C:/Ruby200-x64/lib/ruby/2.0.0/mkmf.rb:1041:in `block in have_header'
from C:/Ruby200-x64/lib/ruby/2.0.0/mkmf.rb:892:in `block in checking_for'
from C:/Ruby200-x64/lib/ruby/2.0.0/mkmf.rb:337:in `block (2 levels) in postpone'
from C:/Ruby200-x64/lib/ruby/2.0.0/mkmf.rb:307:in `open'
from C:/Ruby200-x64/lib/ruby/2.0.0/mkmf.rb:337:in `block in postpone'
from C:/Ruby200-x64/lib/ruby/2.0.0/mkmf.rb:307:in `open'
from C:/Ruby200-x64/lib/ruby/2.0.0/mkmf.rb:333:in `postpone'
from C:/Ruby200-x64/lib/ruby/2.0.0/mkmf.rb:891:in `checking_for'
from C:/Ruby200-x64/lib/ruby/2.0.0/mkmf.rb:1040:in `have_header'
from extconf.rb:16:in `<main>'
Gem files will remain installed in C:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/ffi-1.8.1 for inspection.
Results logged to C:/Ruby200-x64/lib/ruby/gems/2.0.0/gems/ffi-1.8.1/ext/ffi_c/gem_make.out