bug#18390: 24.4.50; REGRESSION: `split-window' error

[Drew Adams <drew.adams@oracle.com>]

Clarification:

0. I meant after the build of 5-25 (copy-pasted the 6-01 build info
first).  However, see below, #2.

1. The error is raised about half the time, and seemingly randomly.
At the prompt, enter the same color name each time (e.g. `blue'),
for consistency.

You can repeatedly try command `palette', and see that sometimes
the error is raised, sometimes not.

You can quit the palette using `q' (in the small palette frame/buffer).
That kills the buffers used for the palette and deletes its frame.

When the error is raised, another frame is opened also, for some reason,
showing only the main palette buffer but with a large char size. Just
close that extra frame and then use `q' in the (small) palette frame, to
be able to repeat the command.

2. I was wrong that the bug was introduced after 2014-05-25.
I can get the same error (also randomly) in that build.  Same thing
with older builds, back to 2013-08-02.

However, I get no error with a build from 2013-07-21 (or earlier),
no matter how many times I try.  So the regression seems to have
been introduced between these two builds:

In GNU Emacs 24.3.50.1 (i686-pc-mingw32)
 of 2013-07-21 on ODIEONE
Bzr revision: 113485 lekktu@gmail.com-20130722012547-e3b7qxn1dba5vf20
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'

In GNU Emacs 24.3.50.1 (i686-pc-mingw32)
 of 2013-08-02 on ODIEONE
Bzr revision: 113660 lekktu@gmail.com-20130802160313-rbi3o6322mz0m3ye
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'