document the GCC4/vax -O0 hacks.

doc/HACKS

@@ -1,4 +1,4 @@
-# $NetBSD: HACKS,v 1.80 2006/06/25 14:24:45 tsutsui Exp $
+# $NetBSD: HACKS,v 1.81 2006/07/01 06:00:41 mrg Exp $
 #
 # This file is intended to document workarounds for currently unsolved
 # (mostly) compiler bugs.
@@ -306,6 +306,15 @@ kcah
 
 port	vax
 
+	hack	gcc4/vax compiler crash
+	cdate	Fri Jun 30 22:39:12 PDT 2006
+	who	mrg
+	file	bin/csh/Makefile	: 1.27
+	file	lib/i18n_module/UTF7/Makefile	: 1.2
+	descr
+		GCC4 on vax crashes.  -O0 stops it happening so far...
+	kcah
+
 	hack	gcc 2.95/vax doesn't like abort being used as function pointer
 	cdate	Tue Dec 13 05:54:50 GMT 2005
 	who	jmc
@@ -313,6 +322,7 @@ port	vax
 	descr
 		Provide a local definition for abort which doesn't include
 		the noreturn attribute which trips up gcc 2.95 on vax.
+	kcah
 	
 	hack	gcc 2.95/vax doesn't have stdbool.h and gettext needs it
 	cdate	Mon May  9 12:16:22 CDT 2005
@@ -326,6 +336,7 @@ port	vax
 		configure checks to work around this. As we don't use configure
 		provide a stdbool.h for vax builds locally in directories from
 		the template provided by the gettext code.
+	kcah
 	
 	hack	gcc 2.95/vax can't handle __used__
 	cdate	Fri May  6 14:30:53 CDT 2005
@@ -336,6 +347,7 @@ port	vax
                 Recent changes to mark this as __used__ to prevent optimization
                 away on sparc64 don't work on 2.95 vax. Ifdef'd back in the
                 old __unused__ if on vax.
+	kcah
 	
 	hack	gcc 2.95/vax cannot handle __builtin_ffs()
 	cdate	Fri Aug 23 21:31:15 CEST 2002
@@ -344,7 +356,7 @@ port	vax
 	descr
 		__builtin_ffs() is ifdef'd away if __vax__. Matt Thomas has
 		added this feature to GCC 3 so it can be removed when switching.
-	
+	kcah
 
 	hack	gcc-vax-libbz2
 	mdate	27 Jun 2002