bug#16172: 24.3.50; C-g in minibuffer hangs Emacs

[Drew Adams]

No info to repro this yet.  But now Emacs is sometimes hanging when I
try to interrupt the current command, which is using the minibuffer,
using C-g (or C-], after C-g at least) repeatedly.  Doesn't seem to
happen all the time, but fairly often.  The Task Manager does NOT
show Emacs gobbling CPU, which surprised me.  But there seems to
be no way to exit Emacs besides killing the process.

In GNU Emacs 24.3.50.1 (i686-pc-mingw32)
 of 2013-12-14 on ODIEONE
Bzr revision: 115521 rudalics@gmx.at-20131214110600-euy4wbseyg78zh72
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --prefix=/c/Devel/emacs/binary --enable-checking=yes,glyphs
 'CFLAGS=-O0 -g3' LDFLAGS=-Lc:/Devel/emacs/lib
 CPPFLAGS=-Ic:/Devel/emacs/include'