'gem install sqlite3' error - ruby-on-rails

Question

When running the gem install sqlite3 command on Mac OS X I experience the following error message:
Users-MacBook-Pro:~ user$ gem install sqlite3
Building native extensions. This could take a while...
ERROR: Error installing sqlite3:
ERROR: Failed to build gem native extension.
/Users/user/.rvm/rubies/ruby-2.1.2/bin/ruby extconf.rb
checking for sqlite3.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}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/Users/user/.rvm/rubies/ruby-2.1.2/bin/ruby
--with-sqlite3-dir
--without-sqlite3-dir
--with-sqlite3-include
--without-sqlite3-include=${sqlite3-dir}/include
--with-sqlite3-lib
--without-sqlite3-lib=${sqlite3-dir}/lib
--enable-local
--disable-local
/Users/user/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/mkmf.rb:456:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.
from /Users/user/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/mkmf.rb:587:in `try_cpp'
from /Users/user/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/mkmf.rb:1120:in `block in find_header'
from /Users/user/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/mkmf.rb:918:in `block in checking_for'
from /Users/user/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/mkmf.rb:351:in `block (2 levels) in postpone'
from /Users/user/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/mkmf.rb:321:in `open'
from /Users/user/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/mkmf.rb:351:in `block in postpone'
from /Users/user/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/mkmf.rb:321:in `open'
from /Users/user/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/mkmf.rb:347:in `postpone'
from /Users/user/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/mkmf.rb:917:in `checking_for'
from /Users/user/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/mkmf.rb:1119:in `find_header'
from extconf.rb:35:in `<main>'
extconf failed, exit code 1
Gem files will remain installed in /Users/user/.rvm/gems/ruby-2.1.2/gems/sqlite3-1.3.9 for inspection.
Results logged to /Users/user/.rvm/gems/ruby-2.1.2/extensions/x86_64-darwin-13/2.1.0-static/sqlite3-1.3.9/gem_make.out
Users-MacBook-Pro:~ user$
I am relatively new to using the terminal, ruby on rails and ruby gems and have been scratching my head (i.e. searching google) for a few hours now, any help would be greatly appreciated. Have tried the sudo command but no luck there.

Answer 1

You should install sqlite3 in your OSX first
brew install sqlite3

Answer 2

Ok, so I ended up throwing the kitchen sink at this one in the end. Here are the steps I took to resolve the issue.
uninstalled RVM link
uninstalled App Store version of xcode as had it previously installed link
ran $ xcode-select --install in terminal to install command line tools
as I already have Homebrew installed I added Homebrews binary path to the front of the $PATH link
$ echo 'export PATH=/usr/local/bin:$PATH' >> ~/.bash_profile
$ source ~/.bash_profile
ran $ brew install sqlite3 command
reinstalled RVM
I believe the steps which mitigated the issue the most were 2,3,4 and 5.
Hope this helps!