If we redefine consistently, make it a suppressed-by-default warning.
If we end up doing the define on pass 2, promote that to a
default-error warning; using a default-error warning allows the user
to demote it should they so wish.
Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Requested-by: C. Masloch <pushbx@38.de>