From bd48a010437816c67bce2c451e85cd041109256f Mon Sep 17 00:00:00 2001
From: Conrad Meyer <cem@FreeBSD.org>
Date: Fri, 19 Apr 2019 20:08:45 +0000
Subject: [PATCH] kernel build: Disable unhelpful GCC warning (tripped after
 r346352)

-Wformat-zero-length does not highlight any particularly wrong code and it
is especially meaningless for device_printf().  Turn it off entirely to
remove a source of false positives.

Sponsored by:	Dell EMC Isilon
---
 sys/conf/kern.mk | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sys/conf/kern.mk b/sys/conf/kern.mk
index 5803f8bb1bc..881ec0d7487 100644
--- a/sys/conf/kern.mk
+++ b/sys/conf/kern.mk
@@ -61,7 +61,8 @@ CWARNEXTRA?=	-Wno-error=address				\
 CWARNEXTRA+=	-Wno-error=misleading-indentation		\
 		-Wno-error=nonnull-compare			\
 		-Wno-error=shift-overflow			\
-		-Wno-error=tautological-compare
+		-Wno-error=tautological-compare			\
+		-Wno-format-zero-length
 .endif
 .if ${COMPILER_VERSION} >= 70200
 CWARNEXTRA+=	-Wno-error=memset-elt-size