Add -Wno-stringop-truncation for GCC8

[ Upstream commit 918b723 ]

This warning appears to not be particularly useful if you ever
actually *want* to truncate a string.

Signed-off-by: Stewart Smith <stewart@linux.ibm.com>

Makefile.main

@@ -31,6 +31,7 @@ CWARNS := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
 	  -Wwrite-strings -Wcast-align \
 	  -Winit-self \
 	  -Wframe-larger-than=1024 \
+	  -Wno-stringop-truncation \
 	  -Werror
 
 # Host tools and options

external/gard/rules.mk

@@ -1,6 +1,6 @@
 .DEFAULT_GOAL := all
 
-override CFLAGS += -O2 -Wall -Werror -I.
+override CFLAGS += -O2 -Wall -Werror -Wno-stringop-truncation -I.
 OBJS      = version.o gard.o units.o
 LIBFLASH_FILES    := libflash.c libffs.c ecc.c blocklevel.c file.c
 LIBFLASH_OBJS     := $(addprefix libflash-, $(LIBFLASH_FILES:.c=.o))