How to use NSTRACE when debugging

Question

I would like to use NSTRACE to see its built-in messages, and create new ones, at various locations within nsterm.m. I imagine/guess that enabling NSTRACE needs to be done when configuring Emacs and it probably requires launching Emacs from the terminal and perhaps an interactive call such as M-x trace-...

Q:  How can I configure Emacs to enable NSTRACE and what other steps are needed to see the messages inside the terminal window?

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For example, here is what I would use if I wanted to see the glyph debugging message inside xdisp.c:   I would use --enable-checking='glyphs' when configuring Emacs; then I would launch Emacs from the command line in a terminal; then I would type M-x trace-redisplay and I could see glyph debugging messages inside the terminal that are created inside xdisp.c like this:

#ifdef GLYPH_DEBUG
  debug_method_add (w, "This is my custom message.");
#endif

Answer 1

Look at src/nsterm.h (http://git.savannah.gnu.org/cgit/emacs.git/tree/src/nsterm.h?id=3f938e1#n41):

/* ==========================================================================

   Trace support

   ========================================================================== */

/* Uncomment the following line to enable trace.

   Uncomment suitable NSTRACE_GROUP_xxx lines to trace more.

   Hint: keep the trailing whitespace -- the version control system
   will reject accidental commits. */

/* #define NSTRACE_ENABLED 1          */

And IMO, questions about development are best asked on emacs-devel.