Improve lua detection
Improve lua detection

lua-config is only available on debian systems
(and already obsoleted). We therefore attempt to use lua config and if
that fails fall back to a simply -llua<ver> etc.

karlnapf/shogun,shogun-toolbox/shogun,karlnapf/shogun,lambday/shogun,geektoni/shogun,Saurabh7/shogun,Saurabh7/shogun,karlnapf/shogun,sorig/shogun,sorig/shogun,karlnapf/shogun,geektoni/shogun,lisitsyn/shogun,karlnapf/shogun,Saurabh7/shogun,lisitsyn/shogun,Saurabh7/shogun,besser82/shogun,lisitsyn/shogun,lisitsyn/shogun,sorig/shogun,besser82/shogun,Saurabh7/shogun,shogun-toolbox/shogun,lisitsyn/shogun,besser82/shogun,lambday/shogun,shogun-toolbox/shogun,lambday/shogun,shogun-toolbox/shogun,geektoni/shogun,shogun-toolbox/shogun,sorig/shogun,lambday/shogun,besser82/shogun,lambday/shogun,besser82/shogun,geektoni/shogun,Saurabh7/shogun,besser82/shogun,geektoni/shogun,karlnapf/shogun,geektoni/shogun,lisitsyn/shogun,Saurabh7/shogun,Saurabh7/shogun,shogun-toolbox/shogun,sorig/shogun,Saurabh7/shogun,sorig/shogun,lambday/shogun