workaround strerror_r ignoring return value warning

because of Werror, just a hack. Affected: ubuntu 13.04 gcc
use POSIX version of esrerror_r
Revert "use POSIX version of esrerror_r"

This reverts commit faa7ac7224a9a616bacec0c034455d156aabdc96.
Merge pull request #40 from breznak/fix_ubuntu_netbeans_cpp

workaround strerror_r ignoring return value warning