次のコマンドを使用して hpricot をインストールしようとしています。
>gem install hpricot -v 0.8.2
Building native extensions. This could take a while...
ERROR: Error installing hpricot:
ERROR: Failed to build gem native extension.
C:/Ruby19/bin/ruby.exe extconf.rb
checking for stdio.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:/Ruby19/bin/ruby
C:/Ruby19/lib/ruby/1.9.1/mkmf.rb:362:in try_do': The complier failed to generate an executable file. (RuntimeError)
You have to install development tools first.
from C:/Ruby19/lib/ruby/1.9.1/mkmf.rb:431:intry_cpp'
from C:/Ruby19/lib/ruby/1.9.1/mkmf.rb:809:in block in have_header'
from C:/Ruby19/lib/ruby/1.9.1/mkmf.rb:668:inblock in checking_for'
from C:/Ruby19/lib/ruby/1.9.1/mkmf.rb:274:in block (2 levels) in postpone'
from C:/Ruby19/lib/ruby/1.9.1/mkmf.rb:248:inopen'
from C:/Ruby19/lib/ruby/1.9.1/mkmf.rb:274:in block in postpone'
from C:/Ruby19/lib/ruby/1.9.1/mkmf.rb:248:inopen'
from C:/Ruby19/lib/ruby/1.9.1/mkmf.rb:270:in postpone'
from C:/Ruby19/lib/ruby/1.9.1/mkmf.rb:667:inchecking_for'
from C:/Ruby19/lib/ruby/1.9.1/mkmf.rb:808:in have_header'
from extconf.rb:2:in'
Gem files will remain installed in C:/Ruby19/lib/ruby/gems/1.9.1/gems/hpricot-0.8.2 for inspection.
Results logged to C:/Ruby19/lib/ruby/gems/1.9.1/gems/hpricot-0.8.2/ext/fast_xs/gem_make.out
「開発ツール」をインストールする必要があると書かれていますが、それが何を指しているのかわかりません。助言がありますか？