Use pkg-config to detect iodbc
Merge branch 'pull-request/411'

* pull-request/411:
  Use pkg-config to detect iodbc
Use pkg-config to detect iodbc
Merge branch 'PHP-5.4' into PHP-5.5

* PHP-5.4:
  Use pkg-config to detect iodbc
Merge branch 'PHP-5.5'

* PHP-5.5:
  Use pkg-config to detect iodbc