another error installing Rails

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

    /usr/bin/ruby -r ./siteconf20150306-6046-1tgmamm.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}/lib64
	--with-make-prog
	--without-make-prog
	--srcdir=.
	--curdir
	--ruby=/usr/bin/ruby
	--help
	--clean
/usr/share/ruby/mkmf.rb:456:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.
	from /usr/share/ruby/mkmf.rb:571:in `block in try_compile'
	from /usr/share/ruby/mkmf.rb:522:in `with_werror'
	from /usr/share/ruby/mkmf.rb:571:in `try_compile'
	from extconf.rb:80:in `nokogiri_try_compile'
	from extconf.rb:87:in `block in add_cflags'
	from /usr/share/ruby/mkmf.rb:621: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 /usr/local/share/gems/gems/nokogiri-1.6.6.2 for inspection.
Results logged to /usr/local/lib64/gems/ruby/nokogiri-1.6.6.2/gem_make.out