Merge tag 'kbuild-v5.18-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Add new environment variables, USERCFLAGS and USERLDFLAGS to allow
   additional flags to be passed to user-space programs.

 - Fix missing fflush() bugs in Kconfig and fixdep

 - Fix a minor bug in the comment format of the .config file

 - Make kallsyms ignore llvm's local labels, .L*

 - Fix UAPI compile-test for cross-compiling with Clang

 - Extend the LLVM= syntax to support LLVM=<suffix> form for using a
   particular version of LLVm, and LLVM=<prefix> form for using custom
   LLVM in a particular directory path.

 - Clean up Makefiles

* tag 'kbuild-v5.18-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: Make $(LLVM) more flexible
  kbuild: add --target to correctly cross-compile UAPI headers with Clang
  fixdep: use fflush() and ferror() to ensure successful write to files
  arch: syscalls: simplify uapi/kapi directory creation
  usr/include: replace extra-y with always-y
  certs: simplify empty certs creation in certs/Makefile
  certs: include certs/signing_key.x509 unconditionally
  kallsyms: ignore all local labels prefixed by '.L'
  kconfig: fix missing '# end of' for empty menu
  kconfig: add fflush() before ferror() check
  kbuild: replace $(if A,A,B) with $(or A,B)
  kbuild: Add environment variables for userprogs flags
  kbuild: unify cmd_copy and cmd_shipped

1 files changed, 27 insertions, 19 deletions

diff --git a/Makefile b/Makefile
index c28c5d91e5c8..18ecb49f1af6 100644
--- a/Makefile
+++ b/Makefile
@@ -424,19 +424,26 @@ HOST_LFS_LDFLAGS := $(shell getconf LFS_LDFLAGS 2>/dev/null)
 HOST_LFS_LIBS := $(shell getconf LFS_LIBS 2>/dev/null)
 
 ifneq ($(LLVM),)
-HOSTCC	= clang
-HOSTCXX	= clang++
+ifneq ($(filter %/,$(LLVM)),)
+LLVM_PREFIX := $(LLVM)
+else ifneq ($(filter -%,$(LLVM)),)
+LLVM_SUFFIX := $(LLVM)
+endif
+
+HOSTCC	= $(LLVM_PREFIX)clang$(LLVM_SUFFIX)
+HOSTCXX	= $(LLVM_PREFIX)clang++$(LLVM_SUFFIX)
 else
 HOSTCC	= gcc
 HOSTCXX	= g++
 endif
 
-export KBUILD_USERCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \
-			      -O2 -fomit-frame-pointer -std=gnu11 \
-			      -Wdeclaration-after-statement
-export KBUILD_USERLDFLAGS :=
+KBUILD_USERHOSTCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \
+			 -O2 -fomit-frame-pointer -std=gnu11 \
+			 -Wdeclaration-after-statement
+KBUILD_USERCFLAGS  := $(KBUILD_USERHOSTCFLAGS) $(USERCFLAGS)
+KBUILD_USERLDFLAGS := $(USERLDFLAGS)
 
-KBUILD_HOSTCFLAGS   := $(KBUILD_USERCFLAGS) $(HOST_LFS_CFLAGS) $(HOSTCFLAGS)
+KBUILD_HOSTCFLAGS   := $(KBUILD_USERHOSTCFLAGS) $(HOST_LFS_CFLAGS) $(HOSTCFLAGS)
 KBUILD_HOSTCXXFLAGS := -Wall -O2 $(HOST_LFS_CFLAGS) $(HOSTCXXFLAGS)
 KBUILD_HOSTLDFLAGS  := $(HOST_LFS_LDFLAGS) $(HOSTLDFLAGS)
 KBUILD_HOSTLDLIBS   := $(HOST_LFS_LIBS) $(HOSTLDLIBS)
@@ -444,14 +451,14 @@ KBUILD_HOSTLDLIBS   := $(HOST_LFS_LIBS) $(HOSTLDLIBS)
 # Make variables (CC, etc...)
 CPP		= $(CC) -E
 ifneq ($(LLVM),)
-CC		= clang
-LD		= ld.lld
-AR		= llvm-ar
-NM		= llvm-nm
-OBJCOPY		= llvm-objcopy
-OBJDUMP		= llvm-objdump
-READELF		= llvm-readelf
-STRIP		= llvm-strip
+CC		= $(LLVM_PREFIX)clang$(LLVM_SUFFIX)
+LD		= $(LLVM_PREFIX)ld.lld$(LLVM_SUFFIX)
+AR		= $(LLVM_PREFIX)llvm-ar$(LLVM_SUFFIX)
+NM		= $(LLVM_PREFIX)llvm-nm$(LLVM_SUFFIX)
+OBJCOPY		= $(LLVM_PREFIX)llvm-objcopy$(LLVM_SUFFIX)
+OBJDUMP		= $(LLVM_PREFIX)llvm-objdump$(LLVM_SUFFIX)
+READELF		= $(LLVM_PREFIX)llvm-readelf$(LLVM_SUFFIX)
+STRIP		= $(LLVM_PREFIX)llvm-strip$(LLVM_SUFFIX)
 else
 CC		= $(CROSS_COMPILE)gcc
 LD		= $(CROSS_COMPILE)ld
@@ -531,6 +538,7 @@ export CPP AR NM STRIP OBJCOPY OBJDUMP READELF PAHOLE RESOLVE_BTFIDS LEX YACC AW
 export PERL PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX
 export KGZIP KBZIP2 KLZOP LZMA LZ4 XZ ZSTD
 export KBUILD_HOSTCXXFLAGS KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS LDFLAGS_MODULE
+export KBUILD_USERCFLAGS KBUILD_USERLDFLAGS
 
 export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS KBUILD_LDFLAGS
 export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE
@@ -1237,8 +1245,8 @@ define filechk_version.h
 	echo \#define LINUX_VERSION_SUBLEVEL $(SUBLEVEL)
 endef
 
-$(version_h): PATCHLEVEL := $(if $(PATCHLEVEL), $(PATCHLEVEL), 0)
-$(version_h): SUBLEVEL := $(if $(SUBLEVEL), $(SUBLEVEL), 0)
+$(version_h): PATCHLEVEL := $(or $(PATCHLEVEL), 0)
+$(version_h): SUBLEVEL := $(or $(SUBLEVEL), 0)
 $(version_h): FORCE
 	$(call filechk,version.h)
 
@@ -1621,7 +1629,7 @@ help:
 	@$(MAKE) -f $(srctree)/Documentation/Makefile dochelp
 	@echo  ''
 	@echo  'Architecture specific targets ($(SRCARCH)):'
-	@$(if $(archhelp),$(archhelp),\
+	@$(or $(archhelp),\
 		echo '  No architecture specific help defined for $(SRCARCH)')
 	@echo  ''
 	@$(if $(boards), \
@@ -1838,7 +1846,7 @@ $(clean-dirs):
 
 clean: $(clean-dirs)
 	$(call cmd,rmfiles)
-	@find $(if $(KBUILD_EXTMOD), $(KBUILD_EXTMOD), .) $(RCS_FIND_IGNORE) \
+	@find $(or $(KBUILD_EXTMOD), .) $(RCS_FIND_IGNORE) \
 		\( -name '*.[aios]' -o -name '*.ko' -o -name '.*.cmd' \
 		-o -name '*.ko.*' \
 		-o -name '*.dtb' -o -name '*.dtbo' -o -name '*.dtb.S' -o -name '*.dt.yaml' \