Since PuTTY depends on lots of features of System 7, have it bale out if

it finds itself running on anything older.  This is better than killing the
whole system with an umimplemented trap.

[originally from svn r2300]

mac/mac.c

@@ -1,4 +1,4 @@
-/* $Id: mac.c,v 1.5 2002/12/06 00:09:34 ben Exp $ */
+/* $Id: mac.c,v 1.6 2002/12/10 01:11:40 ben Exp $ */
 /*
  * Copyright (c) 1999 Ben Harris
  * All rights reserved.
@@ -117,6 +117,11 @@ static void mac_startup(void) {
     InitDialogs(nil);
     cold = 0;
     
+    /* Get base system version (only used if there's no better selector) */
+    if (Gestalt(gestaltSystemVersion, &mac_gestalts.sysvers) != noErr ||
+	(mac_gestalts.sysvers & 0xffff) < 0x700)
+	fatalbox("PuTTY requires System 7 or newer");
+    mac_gestalts.sysvers &= 0xffff;
     /* Find out if we've got Color Quickdraw */
     if (Gestalt(gestaltQuickdrawVersion, &mac_gestalts.qdvers) != noErr)
     	mac_gestalts.qdvers = gestaltOriginalQD;

mac/mac.h

@@ -12,6 +12,7 @@
 #include <Palettes.h>
 
 struct mac_gestalts {
+    long sysvers;
     long qdvers;
     long apprvers;
     long cntlattr;