pg (postgresql) gem installation error and solution [ubuntu 12.04]

pg_gem_installation_error_and_solution.txt

ERROR
=======

$ gem install pg -v '0.17.0'                                                                                   
Building native extensions.  This could take a while...
ERROR:  Error installing pg:
	ERROR: Failed to build gem native extension.

        /home/vishal/.rvm/rubies/ruby-1.9.3-p194/bin/ruby extconf.rb
checking for pg_config... yes
Using config values from /usr/bin/pg_config
checking for libpq-fe.h... yes
checking for libpq/libpq-fs.h... yes
checking for pg_config_manual.h... yes
checking for PQconnectdb() in -lpq... no
checking for PQconnectdb() in -llibpq... no
checking for PQconnectdb() in -lms/libpq... no
Can't find the PostgreSQL client library (libpq)
*** 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
	--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=/home/vishal/.rvm/rubies/ruby-1.9.3-p194/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
	--with-pqlib
	--without-pqlib
	--with-libpqlib
	--without-libpqlib
	--with-ms/libpqlib
	--without-ms/libpqlib


Gem files will remain installed in /home/vishal/.rvm/gems/[email protected]/gems/pg-0.17.0 for inspection.
Results logged to /home/vishal/.rvm/gems/[email protected]/gems/pg-0.17.0/ext/gem_make.out


SOLUTION
==========

$ cp ~/.rvm/usr/lib ~/.rvm/usr/lib_rvm
$ gem install pg -v '0.17.0'                                                                                   
Building native extensions.  This could take a while...
Successfully installed pg-0.17.0
1 gem installed


Reference
-----------
http://stackoverflow.com/a/8874260/1052356