Problem with installing gems

Hey Guys, so i recently started playing around with ROR, however
whenever i
try to install gems i get this message

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

    /Applications/rubystack-1.9.3-22/ruby/bin/ruby extconf.rb

checking for pg_config… yes
Using config values from
/Applications/rubystack-1.9.3-22/postgresql/bin/pg_config
*** 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=/Applications/rubystack-1.9.3-22/ruby/bin/ruby
–with-pg
–without-pg
–with-pg-config
–without-pg-config
–with-pg_config
–without-pg_config
–with-pg-dir
–without-pg-dir
–with-pg-include
–without-pg-include=${pg-dir}/include
–with-pg-lib
–without-pg-lib=${pg-dir}/lib
/Applications/rubystack-1.9.3-22/ruby/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 /Applications/rubystack-1.9.3-22/ruby/lib/ruby/1.9.1/mkmf.rb:461:intry_link0’
from /Applications/rubystack-1.9.3-22/ruby/lib/ruby/1.9.1/mkmf.rb:476:in
try_link' from extconf.rb:39:in

Gem files will remain installed in
/Applications/rubystack-1.9.3-22/ruby/lib/ruby/gems/1.9.1/gems/pg-0.17.1
for inspection.
Results logged to
/Applications/rubystack-1.9.3-22/ruby/lib/ruby/gems/1.9.1/gems/pg-0.17.1/ext/gem_make.out

I dont really get whats happening …

Thanks !

Elton

On Saturday, March 15, 2014 6:35:18 AM UTC, Elton Y. wrote:

Using config values from
/Applications/rubystack-1.9.3-22/postgresql/bin/pg_config

You need development tools installed (c compiler etc). Assuming you’re
on OS X this means installing Xcode and from within Xcode installing the
command line tools (on mavericks you run xcode-select --install )

Fred.