ERROR: Error installing rails: ERROR: Failed to build gem native extension.

hi-Im use cygwin and want to install rails (gem install rails)
I have error please help me

$ gem install rails --version 4.2.1
Building native extensions. This could take a while...
ERROR: Error installing rails:
        ERROR: Failed to build gem native extension.

    /usr/bin/ruby.exe -r ./siteconf20150407-7680-1fo1fpe.rb extconf.rb
checking if the C compiler accepts ... *** 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=/usr/bin/ruby
        --help
        --clean
/usr/share/ruby/2.0.0/mkmf.rb:434:in `try_do': The compiler failed to
generate a
n executable file. (RuntimeError)
You have to install development tools first.
        from /usr/share/ruby/2.0.0/mkmf.rb:549:in `block in try_compile'
        from /usr/share/ruby/2.0.0/mkmf.rb:500:in `with_werror'
        from /usr/share/ruby/2.0.0/mkmf.rb:549:in `try_compile'
        from extconf.rb:80:in `nokogiri_try_compile'
        from extconf.rb:87:in `block in add_cflags'
        from /usr/share/ruby/2.0.0/mkmf.rb:599:in `with_cflags'
        from extconf.rb:86:in `add_cflags'
        from extconf.rb:337:in `<main>'

extconf failed, exit code 1

Gem files will remain installed in
/home/mohammad/.gem/ruby/gems/nokogiri-1.6.6.
2 for inspection.
Results logged to
/home/mohammad/.gem/ruby/extensions/x86_64-cygwin/nokogiri-1.6
.6.2/gem_make.out

hi-Im use cygwin and want to install rails (gem install rails)

I have error please help me

$ gem install rails --version 4.2.1

Building native extensions. This could take a while…

ERROR: Error installing rails:

    ERROR: Failed to build gem native extension.



/usr/bin/ruby.exe -r ./siteconf20150407-7680-1fo1fpe.rb extconf.rb

checking if the C compiler accepts … *** 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=/usr/bin/ruby

    --help

    --clean

/usr/share/ruby/2.0.0/mkmf.rb:434:in `try_do’: The compiler failed to

generate a

n executable file. (RuntimeError)

You have to install development tools first.

    from /usr/share/ruby/2.0.0/mkmf.rb:549:in `block in try_compile'

    from /usr/share/ruby/2.0.0/mkmf.rb:500:in `with_werror'

    from /usr/share/ruby/2.0.0/mkmf.rb:549:in `try_compile'

    from extconf.rb:80:in `nokogiri_try_compile'

    from extconf.rb:87:in `block in add_cflags'

    from /usr/share/ruby/2.0.0/mkmf.rb:599:in `with_cflags'

    from extconf.rb:86:in `add_cflags'

    from extconf.rb:337:in `<main>'

extconf failed, exit code 1

Gem files will remain installed in

/home/mohammad/.gem/ruby/gems/nokogiri-1.6.6.

2 for inspection.

Results logged to

/home/mohammad/.gem/ruby/extensions/x86_64-cygwin/nokogiri-1.6

.6.2/gem_make.out

if you haven’t installed DevKit, so do that, it will solve the problem:

https://github.com/oneclick/rubyinstaller/wiki/Development-Kit#building-the-devkit