Disable the larger/faster code path. While the optimised code path was

indeed quicker, it nonetheless failed to actually fill all the requested
memory with the specified value much of the time if a non-aligned start
address was used.

common/lib/libc/string/memset2.c

@@ -29,7 +29,7 @@
 
 #include <sys/cdefs.h>
 #if defined(LIBC_SCCS) && !defined(lint)
-__RCSID("$NetBSD: memset2.c,v 1.5 2012/03/02 16:22:27 apb Exp $");
+__RCSID("$NetBSD: memset2.c,v 1.6 2021/04/17 05:57:11 simonb Exp $");
 #endif /* LIBC_SCCS and not lint */
 
 #include <sys/types.h>
@@ -47,6 +47,8 @@ __RCSID("$NetBSD: memset2.c,v 1.5 2012/03/02 16:22:27 apb Exp $");
 #include <sys/endian.h>
 #include <machine/types.h>
 
+#define __OPTIMIZE_SIZE__	/* other code path is very broken */
+
 #ifdef TEST
 #include <assert.h>
 #define _DIAGASSERT(a)		assert(a)