Allows for NSA archive mode. In this mode, resources such as BMPs may be read from nsa*.arc, located in the same directory as the executable itself.
The nsa*.arc files themselves are generated by nsaarc.exe, which is found in the SDK.
Please note that you may consecutively name files arc.nsa arc1.nsa arc2.nsa`arc9.nsa, and they will all for the purposes of the interpreter be considered to be part of the same namespace -- as if it is one big archive. You may use this to quickly unpackage and repackage archives for testing.