Merge tag 'kbuild-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Add -s option (strict mode) to merge_config.sh to make it fail when
   any symbol is redefined.

 - Show a warning if a different compiler is used for building external
   modules.

 - Infer --target from ARCH for CC=clang to let you cross-compile the
   kernel without CROSS_COMPILE.

 - Make the integrated assembler default (LLVM_IAS=1) for CC=clang.

 - Add <linux/stdarg.h> to the kernel source instead of borrowing
   <stdarg.h> from the compiler.

 - Add Nick Desaulniers as a Kbuild reviewer.

 - Drop stale cc-option tests.

 - Fix the combination of CONFIG_TRIM_UNUSED_KSYMS and CONFIG_LTO_CLANG
   to handle symbols in inline assembly.

 - Show a warning if 'FORCE' is missing for if_changed rules.

 - Various cleanups

* tag 'kbuild-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (39 commits)
  kbuild: redo fake deps at include/ksym/*.h
  kbuild: clean up objtool_args slightly
  modpost: get the *.mod file path more simply
  checkkconfigsymbols.py: Fix the '--ignore' option
  kbuild: merge vmlinux_link() between ARCH=um and other architectures
  kbuild: do not remove 'linux' link in scripts/link-vmlinux.sh
  kbuild: merge vmlinux_link() between the ordinary link and Clang LTO
  kbuild: remove stale *.symversions
  kbuild: remove unused quiet_cmd_update_lto_symversions
  gen_compile_commands: extract compiler command from a series of commands
  x86: remove cc-option-yn test for -mtune=
  arc: replace cc-option-yn uses with cc-option
  s390: replace cc-option-yn uses with cc-option
  ia64: move core-y in arch/ia64/Makefile to arch/ia64/Kbuild
  sparc: move the install rule to arch/sparc/Makefile
  security: remove unneeded subdir-$(CONFIG_...)
  kbuild: sh: remove unused install script
  kbuild: Fix 'no symbols' warning when CONFIG_TRIM_UNUSD_KSYMS=y
  kbuild: Switch to 'f' variants of integrated assembler flag
  kbuild: Shuffle blank line to improve comment meaning
  ...

lib/Kconfig.debug

@@ -365,6 +365,7 @@ config STRIP_ASM_SYMS
 config READABLE_ASM
 	bool "Generate readable assembler code"
 	depends on DEBUG_KERNEL
+	depends on CC_IS_GCC
 	help
 	  Disable some compiler optimizations that tend to generate human unreadable
 	  assembler output. This may make the kernel slightly slower, but it helps
@@ -383,6 +384,7 @@ config HEADERS_INSTALL
 
 config DEBUG_SECTION_MISMATCH
 	bool "Enable full Section mismatch analysis"
+	depends on CC_IS_GCC
 	help
 	  The section mismatch analysis checks if there are illegal
 	  references from one section to another section.

lib/debug_info.c

@@ -5,8 +5,6 @@
  * CONFIG_DEBUG_INFO_REDUCED. Please do not add actual code. However,
  * adding appropriate #includes is fine.
  */
-#include <stdarg.h>
-
 #include <linux/cred.h>
 #include <linux/crypto.h>
 #include <linux/dcache.h>
@@ -22,6 +20,7 @@
 #include <linux/net.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
+#include <linux/stdarg.h>
 #include <linux/types.h>
 #include <net/addrconf.h>
 #include <net/sock.h>

lib/kasprintf.c

@@ -5,7 +5,7 @@
  *  Copyright (C) 1991, 1992  Linus Torvalds
  */
 
-#include <stdarg.h>
+#include <linux/stdarg.h>
 #include <linux/export.h>
 #include <linux/slab.h>
 #include <linux/types.h>

lib/kunit/string-stream.h

@@ -11,7 +11,7 @@
 
 #include <linux/spinlock.h>
 #include <linux/types.h>
-#include <stdarg.h>
+#include <linux/stdarg.h>
 
 struct string_stream_fragment {
 	struct kunit *test;

lib/vsprintf.c

@@ -17,7 +17,7 @@
  * - scnprintf and vscnprintf
  */
 
-#include <stdarg.h>
+#include <linux/stdarg.h>
 #include <linux/build_bug.h>
 #include <linux/clk.h>
 #include <linux/clk-provider.h>