[PATCH] build: fix build failure with gcc 11.2 by disabling -fcf-protection

[Vineet Gupta]

When doing RV qemu builds with host gcc 11.2, ran into following build failure

| cc -MMD -MP -MT linuxboot_dma.o -MF ./linuxboot_dma.d -O2 -g -march=i486 
-Wall \
|   -Wstrict-prototypes -Wredundant-decls -Wundef -Wwrite-strings 
-Wmissing-prototypes \
|   -Wold-style-declaration -Wold-style-definition -Wtype-limits 
-Wformat-security \
|   -Wformat-y2k -Winit-self -Wignored-qualifiers -Wempty-body -Wnested-externs 
\
|   -Wendif-labels -Wexpansion-to-defined -Wimplicit-fallthrough=2 
-Wno-missing-include-dirs \
|   -Wno-shift-negative-value -Wno-psabi -fno-pie -ffreestanding -IQEMU/include 
\
|   -fno-stack-protector   -m16   -Wa,-32 \
|   -c QEMU/pc-bios/optionrom/linuxboot_dma.c -o linuxboot_dma.o
|cc1: error: ‘-fcf-protection’ is not compatible with this target

Signed-off-by: Vineet Gupta <vineetg@rivosinc.com>
---
This might be a crude fix to the problem
---
 pc-bios/optionrom/Makefile | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/pc-bios/optionrom/Makefile b/pc-bios/optionrom/Makefile
index 5d55d25acca2..8f843ee803c1 100644
--- a/pc-bios/optionrom/Makefile
+++ b/pc-bios/optionrom/Makefile
@@ -22,6 +22,9 @@ override CFLAGS += $(CFLAGS_NOPIE) -ffreestanding 
-I$(TOPSRC_DIR)/include
 override CFLAGS += $(call cc-option, -fno-stack-protector)
 override CFLAGS += $(call cc-option, -m16)
 
+# issue with gcc 11.2
+override CFLAGS += $(call cc-option, -fcf-protection=none)
+
 ifeq ($(filter -m16, $(CFLAGS)),)
 # Attempt to work around compilers that lack -m16 (GCC <= 4.8, clang <= ??)
 # On GCC we add -fno-toplevel-reorder to keep the order of asm blocks with
-- 
2.32.0