Bug: Unable to request replace-string of " \t"

[Bob Rogers]

   When invoking the replace-string command from the keyboard, spaces
seem to get dropped from the first argument to replace-string if
followed by a TAB character.  To reproduce:

   1.  "emacs -Q"

   2.  "M-x replace-string RET SPC TAB RET x RET".  It won't matter that
it doesn't replace anything.  Notice that the SPC and TAB are inserted
into the minibuffer normally, though the prompt after typing RET says
"Replace regexp ^I with: ", indicating that the SPC was deleted.

   3.  You can also do "C-x ESC ESC" to verify that the actual first
argument to replace-string consists of a single TAB.

   Wierd, eh?  I discovered it in an emacs built two weeks ago, and then
reproduced it in one built via "make bootstrap" from CVS as of about
half an hour ago.  I followed the trail as far as read_minibuf, but then
got lost.

                                        -- Bob Rogers
                                           http://rgrjr.dyndns.org/