erl_interface remarks

[Samuel Tardieu]

While playing with interfacing Erlang and Ada, I discovered the following
two things:

   (1) The documentation of ERL_PID_NODE and ERL_PORT_NODE is wrong, as
       those functions return a char *, not a ETERM *

   (2) It would be great if all those macros were also exported as functions
       with the same name (in lower case maybe), so that it is possible to
       use them from another language than C just by linking with the library.
       Right now, I have to have a C wrapper to change the macros into
       functions so that I can call them from Ada. Same hold for defines
       such as ERL_MSG, ERL_TIMEOUT, etc., that could also be exported as
       external variables in addition to defines.

  Sam