Attached to this Email message is an updated version of my patch for GNU
Emacs to provide a partial Windows compatible implementation of
play-sound-internal.  This patch contains two changes from my previous
version:
1) I fixed a warning dealing with incompatible pointer types that occurred
when compiling with MinGW 2.0.
2) I fixed a bug that caused play-sound-internal to fail unless you
specified the full path and file name of the sound file.  In other words,
you could not do the following
  M-x play-sound-internal RET ~/SOUNDS/start.wav RET
Any attempt to call play-sound-file (and thus play-sound-internal) without
specifying the full path and file name would lead to the error message "The
open mciSendString command failed to open the specified sound file" being
displayed.  Now play-sound-internal attempts to obtain the full path and
file name if only a partial file name was specified using the function
expand-file-name (or Fexpand_file_name when called from C source code).

Thus far I have tested this patch on Windows XP using MSVC 6.0 and MinGW
2.0.  Tomorrow I will test this patch on GNU/Linux to make certain I did not
inadvertently cause a compilation error under that platform (I cannot do it
tonight since I am once again reinstalling GNU/Linux on my other computer.
Hopefully this time I know what I am doing and will not make any more stupid
mistakes!).