Utilities for printing debug messages.
eprint message prints to stderr message, followed by a newline and flush. This is
the same as prerr_endline.
eprints message a sexp_of_a prints to stderr message and a as a sexp, followed
by a newline and flush.
eprint_s sexp prints sexp to stderr, followed by a newline and a flush.
eprintf message arg1 ... argn prints to stderr message, with sprintf-style format
characters instantiated, followed by a newline and flush.
Debug.Make produces a debug function used to wrap a function to display arguments
before calling and display results after returning.