>>> "Eli" == Eli Zaretskii <eliz@gnu.org> writes:
   >> 
   >> CFLAGS='-O0 -g3' ./configure --enable-checking='yes,glyphs' --enable-check-lisp-object-type

   > Yes, that's a good beginning.

This dos not work. That description most likely is incomplete.

On the prompt that line gives error, so I presume that  CFLAGS='-O0 -g3'
is a setting either in bash or tcsh shell.

Can you please tell me precisely how this setting should work, and may I
recommend change it in the documentation. Once I have finished
successfully the compilation and the debugging I don't mind doing that.

It might be that for experts like you these things are obvious, for a
C debugging beginner like me, they are not.