Merge tag 'kbuild-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:
 "One of the most remarkable improvements in this cycle is, Kbuild is
  now able to cache the result of shell commands. Some variables are
  expensive to compute, for example, $(call cc-option,...) invokes the
  compiler. It is not efficient to redo this computation every time,
  even when we are not actually building anything. Kbuild creates a
  hidden file ".cache.mk" that contains invoked shell commands and their
  results. The speed-up should be noticeable.

  Summary:

   - Fix arch build issues (hexagon, sh)

   - Clean up various Makefiles and scripts

   - Fix wrong usage of {CFLAGS,LDFLAGS}_MODULE in arch Makefiles

   - Cache variables that are expensive to compute

   - Improve cc-ldopton and ld-option for Clang

   - Optimize output directory creation"

* tag 'kbuild-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (30 commits)
  kbuild: move coccicheck help from scripts/Makefile.help to top Makefile
  sh: decompressor: add shipped files to .gitignore
  frv: .gitignore: ignore vmlinux.lds
  selinux: remove unnecessary assignment to subdir-
  kbuild: specify FORCE in Makefile.headersinst as .PHONY target
  kbuild: remove redundant mkdir from ./Kbuild
  kbuild: optimize object directory creation for incremental build
  kbuild: create object directories simpler and faster
  kbuild: filter-out PHONY targets from "targets"
  kbuild: remove redundant $(wildcard ...) for cmd_files calculation
  kbuild: create directory for make cache only when necessary
  sh: select KBUILD_DEFCONFIG depending on ARCH
  kbuild: fix linker feature test macros when cross compiling with Clang
  kbuild: shrink .cache.mk when it exceeds 1000 lines
  kbuild: do not call cc-option before KBUILD_CFLAGS initialization
  kbuild: Cache a few more calls to the compiler
  kbuild: Add a cache for generated variables
  kbuild: add forward declaration of default target to Makefile.asm-generic
  kbuild: remove KBUILD_SUBDIR_ASFLAGS and KBUILD_SUBDIR_CCFLAGS
  hexagon/kbuild: replace CFLAGS_MODULE with KBUILD_CFLAGS_MODULE
  ...

1 files changed, 147 insertions, 150 deletions

diff --git a/Makefile b/Makefile
index ccb7d5b..efb942a 100644
--- a/Makefile
+++ b/Makefile
@@ -11,6 +11,10 @@ NAME = Fearless Coyote
 # Comments in this file are targeted only to the developer, do not
 # expect to learn how to build the kernel reading this file.
 
+# That's our default target when none is given on the command line
+PHONY := _all
+_all:
+
 # o Do not use make's built-in rules and variables
 #   (this increases performance and avoids hard-to-debug behaviour);
 # o Look for make include files relative to root of kernel src
@@ -117,10 +121,6 @@ ifeq ("$(origin O)", "command line")
   KBUILD_OUTPUT := $(O)
 endif
 
-# That's our default target when none is given on the command line
-PHONY := _all
-_all:
-
 # Cancel implicit rules on top Makefile
 $(CURDIR)/Makefile Makefile: ;
 
@@ -187,15 +187,6 @@ ifeq ("$(origin M)", "command line")
   KBUILD_EXTMOD := $(M)
 endif
 
-# If building an external module we do not care about the all: rule
-# but instead _all depend on modules
-PHONY += all
-ifeq ($(KBUILD_EXTMOD),)
-_all: all
-else
-_all: modules
-endif
-
 ifeq ($(KBUILD_SRC),)
         # building in the source tree
         srctree := .
@@ -207,6 +198,9 @@ else
                 srctree := $(KBUILD_SRC)
         endif
 endif
+
+export KBUILD_CHECKSRC KBUILD_EXTMOD KBUILD_SRC
+
 objtree		:= .
 src		:= $(srctree)
 obj		:= $(objtree)
@@ -215,6 +209,74 @@ VPATH		:= $(srctree)$(if $(KBUILD_EXTMOD),:$(KBUILD_EXTMOD))
 
 export srctree objtree VPATH
 
+# To make sure we do not include .config for any of the *config targets
+# catch them early, and hand them over to scripts/kconfig/Makefile
+# It is allowed to specify more targets when calling make, including
+# mixing *config targets and build targets.
+# For example 'make oldconfig all'.
+# Detect when mixed targets is specified, and make a second invocation
+# of make so .config is not included in this case either (for *config).
+
+version_h := include/generated/uapi/linux/version.h
+old_version_h := include/linux/version.h
+
+no-dot-config-targets := clean mrproper distclean \
+			 cscope gtags TAGS tags help% %docs check% coccicheck \
+			 $(version_h) headers_% archheaders archscripts \
+			 kernelversion %src-pkg
+
+config-targets := 0
+mixed-targets  := 0
+dot-config     := 1
+
+ifneq ($(filter $(no-dot-config-targets), $(MAKECMDGOALS)),)
+	ifeq ($(filter-out $(no-dot-config-targets), $(MAKECMDGOALS)),)
+		dot-config := 0
+	endif
+endif
+
+ifeq ($(KBUILD_EXTMOD),)
+        ifneq ($(filter config %config,$(MAKECMDGOALS)),)
+                config-targets := 1
+                ifneq ($(words $(MAKECMDGOALS)),1)
+                        mixed-targets := 1
+                endif
+        endif
+endif
+# install and modules_install need also be processed one by one
+ifneq ($(filter install,$(MAKECMDGOALS)),)
+        ifneq ($(filter modules_install,$(MAKECMDGOALS)),)
+	        mixed-targets := 1
+        endif
+endif
+
+ifeq ($(mixed-targets),1)
+# ===========================================================================
+# We're called with mixed targets (*config and build targets).
+# Handle them one by one.
+
+PHONY += $(MAKECMDGOALS) __build_one_by_one
+
+$(filter-out __build_one_by_one, $(MAKECMDGOALS)): __build_one_by_one
+	@:
+
+__build_one_by_one:
+	$(Q)set -e; \
+	for i in $(MAKECMDGOALS); do \
+		$(MAKE) -f $(srctree)/Makefile $$i; \
+	done
+
+else
+
+# We need some generic definitions (do not try to remake the file).
+scripts/Kbuild.include: ;
+include scripts/Kbuild.include
+
+# Read KERNELRELEASE from include/config/kernel.release (if it exists)
+KERNELRELEASE = $(shell cat include/config/kernel.release 2> /dev/null)
+KERNELVERSION = $(VERSION)$(if $(PATCHLEVEL),.$(PATCHLEVEL)$(if $(SUBLEVEL),.$(SUBLEVEL)))$(EXTRAVERSION)
+export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION
+
 # SUBARCH tells the usermode build what the underlying arch is.  That is set
 # first, and if a usermode build is happening, the "ARCH=um" on the command
 # line overrides the setting of ARCH below.  If a native build is happening,
@@ -285,9 +347,6 @@ ifeq ($(ARCH),tilegx)
        SRCARCH := tile
 endif
 
-# Where to locate arch specific headers
-hdr-arch  := $(SRCARCH)
-
 KCONFIG_CONFIG	?= .config
 export KCONFIG_CONFIG
 
@@ -308,45 +367,6 @@ HOSTCXXFLAGS := -O2 $(HOST_LFS_CFLAGS)
 HOSTLDFLAGS  := $(HOST_LFS_LDFLAGS)
 HOST_LOADLIBES := $(HOST_LFS_LIBS)
 
-ifeq ($(shell $(HOSTCC) -v 2>&1 | grep -c "clang version"), 1)
-HOSTCFLAGS  += -Wno-unused-value -Wno-unused-parameter \
-		-Wno-missing-field-initializers -fno-delete-null-pointer-checks
-endif
-
-# Decide whether to build built-in, modular, or both.
-# Normally, just do built-in.
-
-KBUILD_MODULES :=
-KBUILD_BUILTIN := 1
-
-# If we have only "make modules", don't compile built-in objects.
-# When we're building modules with modversions, we need to consider
-# the built-in objects during the descend as well, in order to
-# make sure the checksums are up to date before we record them.
-
-ifeq ($(MAKECMDGOALS),modules)
-  KBUILD_BUILTIN := $(if $(CONFIG_MODVERSIONS),1)
-endif
-
-# If we have "make <whatever> modules", compile modules
-# in addition to whatever we do anyway.
-# Just "make" or "make all" shall build modules as well
-
-ifneq ($(filter all _all modules,$(MAKECMDGOALS)),)
-  KBUILD_MODULES := 1
-endif
-
-ifeq ($(MAKECMDGOALS),)
-  KBUILD_MODULES := 1
-endif
-
-export KBUILD_MODULES KBUILD_BUILTIN
-export KBUILD_CHECKSRC KBUILD_SRC KBUILD_EXTMOD
-
-# We need some generic definitions (do not try to remake the file).
-scripts/Kbuild.include: ;
-include scripts/Kbuild.include
-
 # Make variables (CC, etc...)
 AS		= $(CROSS_COMPILE)as
 LD		= $(CROSS_COMPILE)ld
@@ -374,12 +394,11 @@ LDFLAGS_MODULE  =
 CFLAGS_KERNEL	=
 AFLAGS_KERNEL	=
 LDFLAGS_vmlinux =
-CFLAGS_GCOV	:= -fprofile-arcs -ftest-coverage -fno-tree-loop-im $(call cc-disable-warning,maybe-uninitialized,)
 
 # Use USERINCLUDE when you must reference the UAPI directories only.
 USERINCLUDE    := \
-		-I$(srctree)/arch/$(hdr-arch)/include/uapi \
-		-I$(objtree)/arch/$(hdr-arch)/include/generated/uapi \
+		-I$(srctree)/arch/$(SRCARCH)/include/uapi \
+		-I$(objtree)/arch/$(SRCARCH)/include/generated/uapi \
 		-I$(srctree)/include/uapi \
 		-I$(objtree)/include/generated/uapi \
                 -include $(srctree)/include/linux/kconfig.h
@@ -387,40 +406,33 @@ USERINCLUDE    := \
 # Use LINUXINCLUDE when you must reference the include/ directory.
 # Needed to be compatible with the O= option
 LINUXINCLUDE    := \
-		-I$(srctree)/arch/$(hdr-arch)/include \
-		-I$(objtree)/arch/$(hdr-arch)/include/generated \
+		-I$(srctree)/arch/$(SRCARCH)/include \
+		-I$(objtree)/arch/$(SRCARCH)/include/generated \
 		$(if $(KBUILD_SRC), -I$(srctree)/include) \
 		-I$(objtree)/include \
 		$(USERINCLUDE)
 
-KBUILD_CPPFLAGS := -D__KERNEL__
-
+KBUILD_AFLAGS   := -D__ASSEMBLY__
 KBUILD_CFLAGS   := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
 		   -fno-strict-aliasing -fno-common -fshort-wchar \
 		   -Werror-implicit-function-declaration \
 		   -Wno-format-security \
-		   -std=gnu89 $(call cc-option,-fno-PIE)
-
-
+		   -std=gnu89
+KBUILD_CPPFLAGS := -D__KERNEL__
 KBUILD_AFLAGS_KERNEL :=
 KBUILD_CFLAGS_KERNEL :=
-KBUILD_AFLAGS   := -D__ASSEMBLY__ $(call cc-option,-fno-PIE)
 KBUILD_AFLAGS_MODULE  := -DMODULE
 KBUILD_CFLAGS_MODULE  := -DMODULE
 KBUILD_LDFLAGS_MODULE := -T $(srctree)/scripts/module-common.lds
+GCC_PLUGINS_CFLAGS :=
 
-# Read KERNELRELEASE from include/config/kernel.release (if it exists)
-KERNELRELEASE = $(shell cat include/config/kernel.release 2> /dev/null)
-KERNELVERSION = $(VERSION)$(if $(PATCHLEVEL),.$(PATCHLEVEL)$(if $(SUBLEVEL),.$(SUBLEVEL)))$(EXTRAVERSION)
-
-export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION
 export ARCH SRCARCH CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC
 export CPP AR NM STRIP OBJCOPY OBJDUMP HOSTLDFLAGS HOST_LOADLIBES
 export MAKE AWK GENKSYMS INSTALLKERNEL PERL PYTHON UTS_MACHINE
 export HOSTCXX HOSTCXXFLAGS LDFLAGS_MODULE CHECK CHECKFLAGS
 
 export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS LDFLAGS
-export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE CFLAGS_GCOV CFLAGS_KCOV CFLAGS_KASAN CFLAGS_UBSAN
+export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE CFLAGS_KASAN CFLAGS_UBSAN
 export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE
 export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE
 export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL
@@ -462,73 +474,6 @@ ifneq ($(KBUILD_SRC),)
 	    $(srctree) $(objtree) $(VERSION) $(PATCHLEVEL)
 endif
 
-# Support for using generic headers in asm-generic
-PHONY += asm-generic uapi-asm-generic
-asm-generic: uapi-asm-generic
-	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.asm-generic \
-	            src=asm obj=arch/$(SRCARCH)/include/generated/asm
-uapi-asm-generic:
-	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.asm-generic \
-	            src=uapi/asm obj=arch/$(SRCARCH)/include/generated/uapi/asm
-
-# To make sure we do not include .config for any of the *config targets
-# catch them early, and hand them over to scripts/kconfig/Makefile
-# It is allowed to specify more targets when calling make, including
-# mixing *config targets and build targets.
-# For example 'make oldconfig all'.
-# Detect when mixed targets is specified, and make a second invocation
-# of make so .config is not included in this case either (for *config).
-
-version_h := include/generated/uapi/linux/version.h
-old_version_h := include/linux/version.h
-
-no-dot-config-targets := clean mrproper distclean \
-			 cscope gtags TAGS tags help% %docs check% coccicheck \
-			 $(version_h) headers_% archheaders archscripts \
-			 kernelversion %src-pkg
-
-config-targets := 0
-mixed-targets  := 0
-dot-config     := 1
-
-ifneq ($(filter $(no-dot-config-targets), $(MAKECMDGOALS)),)
-	ifeq ($(filter-out $(no-dot-config-targets), $(MAKECMDGOALS)),)
-		dot-config := 0
-	endif
-endif
-
-ifeq ($(KBUILD_EXTMOD),)
-        ifneq ($(filter config %config,$(MAKECMDGOALS)),)
-                config-targets := 1
-                ifneq ($(words $(MAKECMDGOALS)),1)
-                        mixed-targets := 1
-                endif
-        endif
-endif
-# install and modules_install need also be processed one by one
-ifneq ($(filter install,$(MAKECMDGOALS)),)
-        ifneq ($(filter modules_install,$(MAKECMDGOALS)),)
-	        mixed-targets := 1
-        endif
-endif
-
-ifeq ($(mixed-targets),1)
-# ===========================================================================
-# We're called with mixed targets (*config and build targets).
-# Handle them one by one.
-
-PHONY += $(MAKECMDGOALS) __build_one_by_one
-
-$(filter-out __build_one_by_one, $(MAKECMDGOALS)): __build_one_by_one
-	@:
-
-__build_one_by_one:
-	$(Q)set -e; \
-	for i in $(MAKECMDGOALS); do \
-		$(MAKE) -f $(srctree)/Makefile $$i; \
-	done
-
-else
 ifeq ($(config-targets),1)
 # ===========================================================================
 # *config targets only - make sure prerequisites are updated, and descend
@@ -551,6 +496,44 @@ else
 # Build targets only - this includes vmlinux, arch specific targets, clean
 # targets and others. In general all targets except *config targets.
 
+# If building an external module we do not care about the all: rule
+# but instead _all depend on modules
+PHONY += all
+ifeq ($(KBUILD_EXTMOD),)
+_all: all
+else
+_all: modules
+endif
+
+# Decide whether to build built-in, modular, or both.
+# Normally, just do built-in.
+
+KBUILD_MODULES :=
+KBUILD_BUILTIN := 1
+
+# If we have only "make modules", don't compile built-in objects.
+# When we're building modules with modversions, we need to consider
+# the built-in objects during the descend as well, in order to
+# make sure the checksums are up to date before we record them.
+
+ifeq ($(MAKECMDGOALS),modules)
+  KBUILD_BUILTIN := $(if $(CONFIG_MODVERSIONS),1)
+endif
+
+# If we have "make <whatever> modules", compile modules
+# in addition to whatever we do anyway.
+# Just "make" or "make all" shall build modules as well
+
+ifneq ($(filter all _all modules,$(MAKECMDGOALS)),)
+  KBUILD_MODULES := 1
+endif
+
+ifeq ($(MAKECMDGOALS),)
+  KBUILD_MODULES := 1
+endif
+
+export KBUILD_MODULES KBUILD_BUILTIN
+
 ifeq ($(KBUILD_EXTMOD),)
 # Additional helpers built in scripts/
 # Carefully list dependencies so we do not try to build scripts twice
@@ -621,6 +604,11 @@ endif
 # Defaults to vmlinux, but the arch makefile usually adds further targets
 all: vmlinux
 
+KBUILD_CFLAGS	+= $(call cc-option,-fno-PIE)
+KBUILD_AFLAGS	+= $(call cc-option,-fno-PIE)
+CFLAGS_GCOV	:= -fprofile-arcs -ftest-coverage -fno-tree-loop-im $(call cc-disable-warning,maybe-uninitialized,)
+export CFLAGS_GCOV CFLAGS_KCOV
+
 # The arch Makefile can set ARCH_{CPP,A,C}FLAGS to override the default
 # values of the respective KBUILD_* variables
 ARCH_CPPFLAGS :=
@@ -652,7 +640,7 @@ KBUILD_CFLAGS += $(call cc-ifversion, -lt, 0409, \
 KBUILD_CFLAGS	+= $(call cc-option,--param=allow-store-data-races=0)
 
 # check for 'asm goto'
-ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC) $(KBUILD_CFLAGS)), y)
+ifeq ($(call shell-cached,$(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC) $(KBUILD_CFLAGS)), y)
 	KBUILD_CFLAGS += -DCC_HAVE_ASM_GOTO
 	KBUILD_AFLAGS += -DCC_HAVE_ASM_GOTO
 endif
@@ -789,7 +777,7 @@ KBUILD_CFLAGS	+= $(call cc-option,-fdata-sections,)
 endif
 
 # arch Makefile may override CC so keep this after arch Makefile is included
-NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include)
+NOSTDINC_FLAGS += -nostdinc -isystem $(call shell-cached,$(CC) -print-file-name=include)
 CHECKFLAGS     += $(NOSTDINC_FLAGS)
 
 # warn about C99 declaration after statement
@@ -1071,6 +1059,15 @@ prepare0: archprepare gcc-plugins
 # All the preparing..
 prepare: prepare0 prepare-objtool
 
+# Support for using generic headers in asm-generic
+PHONY += asm-generic uapi-asm-generic
+asm-generic: uapi-asm-generic
+	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.asm-generic \
+	            src=asm obj=arch/$(SRCARCH)/include/generated/asm
+uapi-asm-generic:
+	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.asm-generic \
+	            src=uapi/asm obj=arch/$(SRCARCH)/include/generated/uapi/asm
+
 PHONY += prepare-objtool
 prepare-objtool: $(objtool_target)
 
@@ -1139,8 +1136,8 @@ headerdep:
 #Default location for installed headers
 export INSTALL_HDR_PATH = $(objtree)/usr
 
-# If we do an all arch process set dst to include/arch-$(hdr-arch)
-hdr-dst = $(if $(KBUILD_HEADERS), dst=include/arch-$(hdr-arch), dst=include)
+# If we do an all arch process set dst to include/arch-$(SRCARCH)
+hdr-dst = $(if $(KBUILD_HEADERS), dst=include/arch-$(SRCARCH), dst=include)
 
 PHONY += archheaders
 archheaders:
@@ -1158,10 +1155,10 @@ headers_install_all:
 
 PHONY += headers_install
 headers_install: __headers
-	$(if $(wildcard $(srctree)/arch/$(hdr-arch)/include/uapi/asm/Kbuild),, \
+	$(if $(wildcard $(srctree)/arch/$(SRCARCH)/include/uapi/asm/Kbuild),, \
 	  $(error Headers not exportable for the $(SRCARCH) architecture))
 	$(Q)$(MAKE) $(hdr-inst)=include/uapi dst=include
-	$(Q)$(MAKE) $(hdr-inst)=arch/$(hdr-arch)/include/uapi $(hdr-dst)
+	$(Q)$(MAKE) $(hdr-inst)=arch/$(SRCARCH)/include/uapi $(hdr-dst)
 
 PHONY += headers_check_all
 headers_check_all: headers_install_all
@@ -1170,7 +1167,7 @@ headers_check_all: headers_install_all
 PHONY += headers_check
 headers_check: headers_install
 	$(Q)$(MAKE) $(hdr-inst)=include/uapi dst=include HDRCHECK=1
-	$(Q)$(MAKE) $(hdr-inst)=arch/$(hdr-arch)/include/uapi $(hdr-dst) HDRCHECK=1
+	$(Q)$(MAKE) $(hdr-inst)=arch/$(SRCARCH)/include/uapi $(hdr-dst) HDRCHECK=1
 
 # ---------------------------------------------------------------------------
 # Kernel selftest
@@ -1283,7 +1280,7 @@ CLEAN_DIRS  += $(MODVERDIR)
 # Directories & files removed with 'make mrproper'
 MRPROPER_DIRS  += include/config usr/include include/generated          \
 		  arch/*/include/generated .tmp_objdiff
-MRPROPER_FILES += .config .config.old .version .old_version \
+MRPROPER_FILES += .config .config.old .version \
 		  Module.symvers tags TAGS cscope* GPATH GTAGS GRTAGS GSYMS \
 		  signing_key.pem signing_key.priv signing_key.x509	\
 		  x509.genkey extra_certificates signing_key.x509.keyid	\
@@ -1393,7 +1390,7 @@ help:
 	@echo  '  export_report   - List the usages of all exported symbols'
 	@echo  '  headers_check   - Sanity check on exported headers'
 	@echo  '  headerdep       - Detect inclusion cycles in headers'
-	@$(MAKE) -f $(srctree)/scripts/Makefile.help checker-help
+	@echo  '  coccicheck      - Check with Coccinelle'
 	@echo  ''
 	@echo  'Kernel selftest:'
 	@echo  '  kselftest       - Build and run kernel selftest (run as root)'
@@ -1556,6 +1553,7 @@ clean: $(clean-dirs)
 		-o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
 		-o -name '*.symtypes' -o -name 'modules.order' \
 		-o -name modules.builtin -o -name '.tmp_*.o.*' \
+		-o -name .cache.mk \
 		-o -name '*.c.[012]*.*' \
 		-o -name '*.ll' \
 		-o -name '*.gcno' \) -type f -print | xargs rm -f
@@ -1702,8 +1700,7 @@ cmd_crmodverdir = $(Q)mkdir -p $(MODVERDIR) \
 
 # read all saved command lines
 
-targets := $(wildcard $(sort $(targets)))
-cmd_files := $(wildcard .*.cmd $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
+cmd_files := $(wildcard .*.cmd $(foreach f,$(sort $(targets)),$(dir $(f)).$(notdir $(f)).cmd))
 
 ifneq ($(cmd_files),)
   $(cmd_files): ;	# Do not try to update included dependency files