[krbdev.mit.edu #3954] gssapi mechglue pname_to_uid: include or not?

[Jeffrey Altman via RT]

The gssapi mechglue function pointer pname_to_uid is not implemented. 
However, the function pointer is still specified in the mechglue data
structure.  On Windows the function declaraton does not compile because
the type 'uid_t' does not have a definition.

The following decision needs to be made.  Either we add a type
declaration to win-mac.h for 'uid_t' or we remove the references to
'pname_to_uid' from the mechglue and spnego.

The concerns are whether or not we want to maintain data structure
compatibility with Sun even though we are unlike to implement this
functionality.