display version and build info at startup (trunk only)

Tested on the unix port; I've updated as many other ports as I can figure
out but they're not tested.  See window.doc for info on the changed banner
lines.  Also adds the ability to override the generic "Unix" port - used now to get
"MacOSX" into the version line instead of "Unix" (so we don't scare people who don't
know what's going on).

win/win32/mhsplash.c

@@ -8,6 +8,7 @@
 #include "mhsplash.h"
 #include "mhmsg.h"
 #include "mhfont.h"
+#include "date.h"
 #include "patchlevel.h"
 #include "dlb.h"
 
@@ -85,8 +86,8 @@ void mswin_display_splash_window (BOOL show_ver)
 	    clientrt.right - 2 * SPLASH_OFFSET_X, controlrt.bottom, TRUE);
 
 	/* Fill the text control */
-	Sprintf (buf, "%s\r\n%s\r\n%s\r\n\r\n", COPYRIGHT_BANNER_A, COPYRIGHT_BANNER_B,
-             COPYRIGHT_BANNER_C);
+	Sprintf (buf, "%s\r\n%s\r\n%s\r\n%s\r\n\r\n", COPYRIGHT_BANNER_A, COPYRIGHT_BANNER_B,
+             COPYRIGHT_BANNER_C, COPYRIGHT_BANNER_D);
 	strsize = strlen(buf);
 
 	if (show_ver) {