fix building coreboot images on i686 hosts

firstly, memtest86+ is currently not cross compiled and
relies on 64-bit headers (x86_64 only). a 32-bit distro
is unlikely to be able to build 64-bit binaries.

secondly: vboot throws a build error due to -Werror when
building on 32-bit hosts. we rely on vboot code to build
cbfstool, so turn off -Werror on vboot

that's all. 32-bit hosts are not recommended; it is assumed
that you are building on an x86_64 host. work will go into
the build system at a later date to make it more portable,
by cross compiling everything, but this should fix 32-bit
for now.

there are some x60/t60 users who still want to build roms,
so let's allow them that possibility.

Signed-off-by: Leah Rowe <leah@libreboot.org>

config/submodule/coreboot/i945/vboot/patches/0001-don-t-treat-warnings-as-errors.patch

@@ -0,0 +1,35 @@
+From 59c393f2a928770c2d397bc93d388543c2d94dab Mon Sep 17 00:00:00 2001
+From: Leah Rowe <info@minifree.org>
+Date: Tue, 21 May 2024 23:22:50 +0100
+Subject: [PATCH 1/1] don't treat warnings as errors
+
+Signed-off-by: Leah Rowe <info@minifree.org>
+---
+ Makefile | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/Makefile b/Makefile
+index a4390522..d2ec9aa3 100644
+--- a/Makefile
++++ b/Makefile
+@@ -125,7 +125,7 @@ endif
+ # Provide default CC and CFLAGS for firmware builds; if you have any -D flags,
+ # please add them after this point (e.g., -DVBOOT_DEBUG).
+ DEBUG_FLAGS := $(if $(filter-out 0,${DEBUG}),-g -Og,-g -Os)
+-WERROR := -Werror
++WERROR := -Wno-error -w
+ FIRMWARE_FLAGS := -nostdinc -ffreestanding -fno-builtin -fno-stack-protector
+ COMMON_FLAGS := -pipe ${WERROR} -Wall -Wstrict-prototypes -Wtype-limits \
+ 	-Wundef -Wmissing-prototypes -Wno-trigraphs -Wredundant-decls -Wshadow \
+@@ -162,7 +162,7 @@ CFLAGS += -std=gnu11
+ # returns: $(1) if compiler was successful, empty string otherwise
+ test_ccflag = $(shell \
+ 	printf "$(2)\nvoid _start(void) {}\n" | \
+-	$(CC) -nostdlib -Werror $(1) -xc -c - -o /dev/null \
++	$(CC) -nostdlib -Wno-error -w $(1) -xc -c - -o /dev/null \
+ 	>/dev/null 2>&1 && echo "$(1)")
+ 
+ COMMON_FLAGS += $(call test_ccflag,-Wimplicit-fallthrough)
+-- 
+2.39.2
+