bash: Do not assume bash is installed in /bin/bash

There are systems that do not provide a bash in the standard
installation. Use "/usr/bin/env bash" to execute a bash. This
is needed for FreeBSD.
freebsd: Add a working FreeBSD 10.0-RELEASE/11-CURRENT config

The ThirdPartyLibrary name handling is the most nasty part as it
shows issues with the inheritance and assuming "linux" = "unix".
Merge pull request #59 from zecke/freebsd-build

Freebsd build