Add a patch to fix building under GCC 15

GCC 15 defaults to gnu23, breaking some parts of the kernel which
doesn't receive the "-std=gnu11" flag.

Add a patch to explicitly pass that flag to arch/x86/boot/compressed
until upstream makes up their mind on how to fix this.

Signed-off-by: Sergio Lopez <[email protected]>

Author: slp

Makefile

@@ -6,8 +6,8 @@ KERNEL_PATCHES = $(shell find patches/ -name "0*.patch" | sort)
 KERNEL_C_BUNDLE = kernel.c
 
 ABI_VERSION = 4
-FULL_VERSION = 4.7.0
-TIMESTAMP = "Wed Dec 11 20:34:13 CET 2024"
+FULL_VERSION = 4.7.1
+TIMESTAMP = "Mon Jan 20 16:45:32 CET 2025"
 
 KERNEL_FLAGS = KBUILD_BUILD_TIMESTAMP=$(TIMESTAMP)
 KERNEL_FLAGS += KBUILD_BUILD_USER=root

patches/0023-arch-x86-boot-compressed-use-std-gnu11-flag.patch

@@ -0,0 +1,44 @@
+From ed8a28bfd78e90ae9fe27b6eafe1affd93a80f71 Mon Sep 17 00:00:00 2001
+From: Sergio Lopez <[email protected]>
+Date: Mon, 20 Jan 2025 16:38:26 +0100
+Subject: [PATCH 23/27] arch/x86,efi/libstub: use -std=gnu11 flag
+
+GCC 15 defaults to gnu23, but the kernel is not compatible to that
+standard. Other parts of the kernel use -std=gnu11, so let's do the same
+in arch/x86/boot/compressed and efi/libstub.
+
+Signed-off-by: Sergio Lopez <[email protected]>
+---
+ arch/x86/boot/compressed/Makefile     | 2 +-
+ drivers/firmware/efi/libstub/Makefile | 2 +-
+ 2 files changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
+index f2051644de94..5c8b86dfb1ea 100644
+--- a/arch/x86/boot/compressed/Makefile
++++ b/arch/x86/boot/compressed/Makefile
+@@ -24,7 +24,7 @@ targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \
+ # case of cross compiling, as it has the '--target=' flag, which is needed to
+ # avoid errors with '-march=i386', and future flags may depend on the target to
+ # be valid.
+-KBUILD_CFLAGS := -m$(BITS) -O2 $(CLANG_FLAGS)
++KBUILD_CFLAGS := -std=gnu11 -m$(BITS) -O2 $(CLANG_FLAGS)
+ KBUILD_CFLAGS += -fno-strict-aliasing -fPIE
+ KBUILD_CFLAGS += -Wundef
+ KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
+diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
+index ed4e8ddbe76a..78cdf380ffcc 100644
+--- a/drivers/firmware/efi/libstub/Makefile
++++ b/drivers/firmware/efi/libstub/Makefile
+@@ -36,7 +36,7 @@ cflags-$(CONFIG_LOONGARCH)	+= -fpie
+ cflags-$(CONFIG_EFI_PARAMS_FROM_FDT)	+= -I$(srctree)/scripts/dtc/libfdt
+ 
+ KBUILD_CFLAGS			:= $(subst $(CC_FLAGS_FTRACE),,$(cflags-y)) \
+-				   -Os -DDISABLE_BRANCH_PROFILING \
++				   -std=gnu11 -Os -DDISABLE_BRANCH_PROFILING \
+ 				   -include $(srctree)/include/linux/hidden.h \
+ 				   -D__NO_FORTIFY \
+ 				   -ffreestanding \
+-- 
+2.45.2
+