将gem'devise'添加到我的gem文件并运行$ bundle install之后，我得到以下内容：
Installing bcrypt-ruby (3.1.1) with native extensions
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.
/usr/local/rvm/rubies/ruby-1.9.3-p392/bin/ruby extconf.rb
checking for ruby/util.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.
An error occurred while installing bcrypt-ruby (3.1.1), and Bundler cannot continue.
Make sure that `gem install bcrypt-ruby -v '3.1.1'` succeeds before bundling.
这是终端返回的内容，单独尝试安装bcrypt，但它不会工作。
提前谢谢！
Anonyos-iMac:omrails manny$ bundle install
Fetching gem metadata from https://rubygems.org/...........
Fetching gem metadata from https://rubygems.org/..
Resolving dependencies...
Enter your password to install the bundled RubyGems to your system:
Using rake (10.1.0)
Using i18n (0.6.4)
Using multi_json (1.7.7)
Using activesupport (3.2.12)
Using builder (3.0.4)
Using activemodel (3.2.12)
Using erubis (2.7.0)
Using journey (1.0.4)
Using rack (1.4.5)
Using rack-cache (1.2)
Using rack-test (0.6.2)
Using hike (1.2.3)
Using tilt (1.4.1)
Using sprockets (2.2.2)
Using actionpack (3.2.12)
Using mime-types (1.23)
Using polyglot (0.3.3)
Using treetop (1.4.14)
Using mail (2.4.4)
Using actionmailer (3.2.12)
Using arel (3.0.2)
Using tzinfo (0.3.37)
Using activerecord (3.2.12)
Using activeresource (3.2.12)
Installing bcrypt-ruby (3.1.1) with native extensions
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.
/usr/local/rvm/rubies/ruby-1.9.3-p392/bin/ruby extconf.rb
checking for ruby/util.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`enter code here`
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/usr/local/rvm/rubies/ruby-1.9.3-p392/bin/ruby
/usr/local/rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/mkmf.rb:381:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.
from /usr/local/rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/mkmf.rb:506:in `try_cpp'
from /usr/local/rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/mkmf.rb:931:in `block in have_header'
from /usr/local/rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/mkmf.rb:790:in `block in checking_for'
from /usr/local/rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/mkmf.rb:284:in `block (2 levels) in postpone'
from /usr/local/rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/mkmf.rb:254:in `open'
from /usr/local/rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/mkmf.rb:284:in `block in postpone'
from /usr/local/rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/mkmf.rb:254:in `open'
from /usr/local/rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/mkmf.rb:280:in `postpone'
from /usr/local/rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/mkmf.rb:789:in `checking_for'
from /usr/local/rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/mkmf.rb:930:in `have_header'
from extconf.rb:14:in `<main>'
Gem files will remain installed in /Users/manny/.bundler/tmp/1023/gems/bcrypt-ruby-3.1.1 for inspection.
Results logged to /Users/manny/.bundler/tmp/1023/gems/bcrypt-ruby-3.1.1/ext/mri/gem_make.out
An error occurred while installing bcrypt-ruby (3.1.1), and Bundler cannot continue.
Make sure that `gem install bcrypt-ruby -v '3.1.1'` succeeds before bundling.