This library is to be used by multithreaded programs that need to access
the kauth and auth library interfaces.  The primary method used to obtain
thread safety in these libraries is to lock/unlock a recursive global
mutex at the entry point of every public function in the library.

However, not all public functions are made thread safe since not all 
functions are needed by the NT admin work.  In particular, there are
many public functions that make up decendants of the functions
we wish to use that weren't modified, since these functions will be 
protected by the locking at a higher level function.

To prevent people from using non-thread safe functions, platform 
specific methods are used to limit the functions exported by the 
library (using def files under NT and mapfiles under Solaris).  For 
most non-exported functions, it should be trivial to make the 
transformation to thread safe by simply locking/ unlocking the 
global mutex at the beginning/end of the function.
