I'm trying to setup my VPS (CentOS 6.4) with ruby on rails and postgres.

I installed ruby (2.1.0p0), rails (4.1.0), and postgresql (9.3.4) with no problem.

When I try create new rails app (rails new new_app -d postgresql) it stops when installing the pg gem. I've looked into all SO posts about this error and tried pretty much everything I could find. The most suggested was to run "yum install postgresql-devel" and still didn't work.

Below you can find the ssh output and the mkmf.log. Let me know if need more information...

---

Output

Building native extensions.  This could take a while...
ERROR:  Error installing pg:
ERROR: Failed to build gem native extension.

/home/deploy/.rvm/rubies/ruby-2.1.0/bin/ruby extconf.rb
checking for pg_config... yes
Using config values from /usr/bin/pg_config
checking for libpq-fe.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=/home/deploy/.rvm/rubies/ruby-2.1.0/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
/home/deploy/.rvm/rubies/ruby-2.1.0/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 /home/deploy/.rvm/rubies/ruby-2.1.0/lib/ruby/2.1.0/mkmf.rb:587:in `try_cpp'
    from /home/deploy/.rvm/rubies/ruby-2.1.0/lib/ruby/2.1.0/mkmf.rb:1120:in `block in find_header'
    from /home/deploy/.rvm/rubies/ruby-2.1.0/lib/ruby/2.1.0/mkmf.rb:918:in `block in checking_for'
    from /home/deploy/.rvm/rubies/ruby-2.1.0/lib/ruby/2.1.0/mkmf.rb:351:in `block (2 levels) in postpone'
    from /home/deploy/.rvm/rubies/ruby-2.1.0/lib/ruby/2.1.0/mkmf.rb:321:in `open'
    from /home/deploy/.rvm/rubies/ruby-2.1.0/lib/ruby/2.1.0/mkmf.rb:351:in `block in postpone'
    from /home/deploy/.rvm/rubies/ruby-2.1.0/lib/ruby/2.1.0/mkmf.rb:321:in `open'
    from /home/deploy/.rvm/rubies/ruby-2.1.0/lib/ruby/2.1.0/mkmf.rb:347:in `postpone'
    from /home/deploy/.rvm/rubies/ruby-2.1.0/lib/ruby/2.1.0/mkmf.rb:917:in `checking_for'
    from /home/deploy/.rvm/rubies/ruby-2.1.0/lib/ruby/2.1.0/mkmf.rb:1119:in `find_header'
    from extconf.rb:48:in `'

extconf failed, exit code 1

---

mkmf.log

"gcc -o conftest -I/home/deploy/.rvm/rubies/ruby-2.1.0/include/ruby-2.1.0/x86_64-linux -I/home/deploy/.rvm/rubies/ruby-2.1.0/include/ruby-2.1.0/ruby/backward -I/home/deploy/.rvm/rubies/ruby-2.1.0/include/ruby-2.1.0 -I. -I/usr/include     -O3 -fno-fast-math -ggdb3 -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wunused-variable -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wimplicit-function-declaration  -fPIC conftest.c  -L. -L/home/deploy/.rvm/rubies/ruby-2.1.0/lib -Wl,-R/home/deploy/.rvm/rubies/ruby-2.1.0/lib -L/usr/lib64 -Wl,-R/usr/lib64 -L. -fstack-protector -rdynamic -Wl,-export-dynamic     -Wl,-rpath,'/../lib' -Wl,-R -Wl,'/../lib' -L'/../lib' -lruby  -lpthread -lrt -ldl -lcrypt -lm   -lc"
gcc: error trying to exec 'as': execvp: Permission denied
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: int main(int argc, char **argv)
4: {
5:   return 0;
6: }
/* end */

Before:

For Centos 6: Right install Postgres 9.* with this guide.

After:

yum install postgresql-libs postgresql-devel

Helpful instruction:

How to setup RoR with Postgres