Mac dynloading changed to allow multiple modules to live in with each
other in the same file.

both enabled with USE_SHARED_LIBRARY, now there's also
USE_MAC_DYNAMIC_LOADING).

Added a few other USE_ defines for optional modules to nonshared
config (they're not included in the base shared library)

- Use Universal Headers as input
- Change addpack calls to not depend on Guido's disklayout
- Checkge testprograms to use new names for some functions

- Use Universal Headers as input
- Change addpack calls to not depend on Guido's disklayout
- Checkge testprograms to use new names for some functions

- Make the stuff run on Jack's machine (and hopefully all machines) in
  stead of Guido's only (addpack stuff)
- Use the Universal Headers in stead of the Think headers
- Fixed the test programs to use the new routine names

values are gotten from the cl module.  CL_old is there in case cl
doesn't exist.

Also added Irix 5.3 constants.