bug#12371: 24.2.50; macroexpand-all reporting warnings to *Compile-Log*

[Christopher Schmidt]

emacs -q
M-: (macroexpand-all '(mapc '(lambda ()) nil)) RET

Debugger entered--Lisp error: (void-function byte-compile-log-warning)

emacs -q
M-x load-library RET bytecomp RET
M-: (macroexpand-all '(mapc '(lambda ()) nil)) RET

A *Compile-Log* buffer appears, with the following content

    Warning: (lambda nil ...) quoted with ' rather than with #'

This is utterly confusing.  There is no compilation going on.  (Another
user experience regarding this issue can be found in bug report 12362 -
<87392vtj24.fsf@jidanni.org>.)

macroexp--expand-all, which is the originator of the warning, calls
byte-compile-log-warning without consulting byte-compile-warnings.

I think the warning message should include a hint that it was generated
by macroexpanding code and byte-compile-warnings should be consulted as
well.

GNU Emacs 24.2.50.2 (x86_64-unknown-linux-gnu, GTK+ Version 2.24.10) of
2012-09-06.

        Christopher