Re: compile.el::grep-program - should it use egrep instead of grep?

[Richard M. Stallman]

    There is

       (defvar grep-program "egrep" ...)

    in compile.el,

No there isn't.  The default value of grep-program is "grep" or "zgrep".
What version are you looking at?

     but in some systems the grep is the old one, which does
    not provide the extended syntax. Would it be possible to set this by
    default to 'egrep'?

Sorry, no.  Emacs's regexp syntax is based on the grep syntax rather
than the egrep syntax.