[bug#60776] [PATCH] distdir/emacs: avoid `test -d` with MKDIR_P

[Karl Berry]

    imo we overly rely on explicit @ in many places which can make debugging
    failures painful.

FWIW, I agree. Although I see no @ here.

    if we ever get to that day, we'd use $(AM_V_at) in
    this location.

Ok by me. --thanks, karl.