FOR MSWINDOWS PLATFORMS ONLY

After downloading 21.4.2, also download and apply the patch

		   mswindows-21.4.2-21.4.2msw.patch

This patch fixes two build problems discovered immediately after
release of 21.4.2.

(1) The include of events-mod.h went missing from src/event-msw.c.
    Prevents build on all Windows platforms.
(2) ./configure finds linux-soundplay, which causes a fatal link error.
    Prevents build on Cygwin, only.