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:in `try_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 `<main>'

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

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.

/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:in `try_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 `<main>'

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.