[root@pcmk1 ~]# gem install rpam
Fetching: rpam-1.0.1.gem (100%)
Building native extensions.  This could take a while...
ERROR:  Error installing rpam:
	ERROR: Failed to build gem native extension.

    /usr/bin/ruby extconf.rb
checking for security/pam_appl.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}/lib64
	--with-make-prog
	--without-make-prog
	--srcdir=.
	--curdir
	--ruby=/usr/bin/ruby
/usr/share/ruby/mkmf.rb:431: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:562:in `try_cpp'
	from /usr/share/ruby/mkmf.rb:1041:in `block in have_header'
	from /usr/share/ruby/mkmf.rb:892:in `block in checking_for'
	from /usr/share/ruby/mkmf.rb:337:in `block (2 levels) in postpone'
	from /usr/share/ruby/mkmf.rb:307:in `open'
	from /usr/share/ruby/mkmf.rb:337:in `block in postpone'
	from /usr/share/ruby/mkmf.rb:307:in `open'
	from /usr/share/ruby/mkmf.rb:333:in `postpone'
	from /usr/share/ruby/mkmf.rb:891:in `checking_for'
	from /usr/share/ruby/mkmf.rb:1040:in `have_header'
	from extconf.rb:6:in `<main>'


Gem files will remain installed in /usr/local/share/gems/gems/rpam-1.0.1 for inspection.
Results logged to /usr/local/share/gems/gems/rpam-1.0.1/ext/Rpam/gem_make.out