Makefile - qemu - Git at Google

 # Makefile for QEMU.

 ifneq ($(words $(subst :, ,$(CURDIR))), 1)
   $(error main directory cannot contain spaces nor colons)
 endif

 # Always point to the root of the build tree (needs GNU make).
 BUILD_DIR=$(CURDIR)

 # Before including a proper config-host.mak, assume we are in the source tree
 SRC_PATH=.

 # Don't use implicit rules or variables
 # we have explicit rules for everything
 MAKEFLAGS += -rR

 # Usage: $(call quiet-command,command and args,"NAME","args to print")
 # This will run "command and args", and either:
 #  if V=1 just print the whole command and args
 #  otherwise print the 'quiet' output in the format "  NAME     args to print"
 # NAME should be a short name of the command, 7 letters or fewer.
 # If called with only a single argument, will print nothing in quiet mode.
 quiet-command-run = $(if $(V),,$(if $2,printf "  %-7s %s\n" $2 $3 && ))$1
 quiet-@ = $(if $(V),,@)
 quiet-command = $(quiet-@)$(call quiet-command-run,$1,$2,$3)

 UNCHECKED_GOALS := %clean TAGS cscope ctags dist \
     help check-help print-% \
     docker docker-% vm-help vm-test vm-build-%

 # All following code might depend on configuration variables
 ifneq ($(wildcard config-host.mak),)
 # Put the all: rule here so that config-host.mak can contain dependencies.
 all:
 include config-host.mak

 git-submodule-update:

 .PHONY: git-submodule-update

 git_module_status := $(shell \
   cd '$(SRC_PATH)' && \
   GIT="$(GIT)" ./scripts/git-submodule.sh status $(GIT_SUBMODULES); \
   echo $$?; \
 )

 ifeq (1,$(git_module_status))
 ifeq (no,$(GIT_UPDATE))
 git-submodule-update:
 	$(call quiet-command, \
             echo && \
             echo "GIT submodule checkout is out of date. Please run" && \
             echo "  scripts/git-submodule.sh update $(GIT_SUBMODULES)" && \
             echo "from the source directory checkout $(SRC_PATH)" && \
             echo && \
             exit 1)
 else
 git-submodule-update:
 	$(call quiet-command, \
           (cd $(SRC_PATH) && GIT="$(GIT)" ./scripts/git-submodule.sh update $(GIT_SUBMODULES)), \
           "GIT","$(GIT_SUBMODULES)")
 endif
 endif

 export NINJA=./ninjatool

 # Running meson regenerates both build.ninja and ninjatool, and that is
 # enough to prime the rest of the build.
 ninjatool: build.ninja

 Makefile.ninja: build.ninja ninjatool
 	./ninjatool -t ninja2make --omit clean dist uninstall cscope TAGS ctags < $< > $@
 -include Makefile.ninja

 ${ninja-targets-c_COMPILER} ${ninja-targets-cpp_COMPILER}: .var.command += -MP

 # If MESON is empty, the rule will be re-evaluated after Makefiles are
 # reread (and MESON won't be empty anymore).
 ifneq ($(MESON),)
 Makefile.mtest: build.ninja scripts/mtest2make.py
 	$(MESON) introspect --targets --tests --benchmarks | $(PYTHON) scripts/mtest2make.py > $@
 -include Makefile.mtest
 endif

 Makefile: .git-submodule-status
 .git-submodule-status: git-submodule-update config-host.mak

 # Check that we're not trying to do an out-of-tree build from
 # a tree that's been used for an in-tree build.
 ifneq ($(realpath $(SRC_PATH)),$(realpath .))
 ifneq ($(wildcard $(SRC_PATH)/config-host.mak),)
 $(error This is an out of tree build but your source tree ($(SRC_PATH)) \
 seems to have been used for an in-tree build. You can fix this by running \
 "$(MAKE) distclean && rm -rf *-linux-user *-softmmu" in your source tree)
 endif
 endif

 config-host.mak: $(SRC_PATH)/configure $(SRC_PATH)/pc-bios $(SRC_PATH)/VERSION
 	@echo $@ is out-of-date, running configure
 	@if test -f meson-private/coredata.dat; then \
 	  ./config.status --skip-meson; \
 	else \
 	  ./config.status; \
 	fi

 # Force configure to re-run if the API symbols are updated
 ifeq ($(CONFIG_PLUGIN),y)
 config-host.mak: $(SRC_PATH)/plugins/qemu-plugins.symbols

 .PHONY: plugins
 plugins:
 	$(call quiet-command,\
 		$(MAKE) $(SUBDIR_MAKEFLAGS) -C contrib/plugins V="$(V)", \
 		"BUILD", "example plugins")
 endif

 else
 config-host.mak:
 ifneq ($(filter-out $(UNCHECKED_GOALS),$(MAKECMDGOALS)),$(if $(MAKECMDGOALS),,fail))
 	@echo "Please call configure before running make!"
 	@exit 1
 endif
 endif

 # Only needed in case Makefile.ninja does not exist.
 .PHONY: ninja-clean ninja-distclean clean-ctlist
 clean-ctlist:
 ninja-clean::
 ninja-distclean::
 build.ninja: config-host.mak

 # Don't try to regenerate Makefile or configure
 # We don't generate any of them
 Makefile: ;
 configure: ;

 .PHONY: all clean distclean install \
 	recurse-all dist msi FORCE

 SUBDIR_MAKEFLAGS=$(if $(V),,--no-print-directory --quiet)

 include $(SRC_PATH)/tests/Makefile.include

 all: recurse-all
 Makefile: $(addsuffix /all, $(SUBDIRS))

 # LIBFDT_lib="": avoid breaking existing trees with objects requiring -fPIC
 DTC_MAKE_ARGS=-I$(SRC_PATH)/dtc VPATH=$(SRC_PATH)/dtc -C dtc V="$(V)" LIBFDT_lib=""
 DTC_CFLAGS=$(CFLAGS) $(QEMU_CFLAGS)
 DTC_CPPFLAGS=-I$(SRC_PATH)/dtc/libfdt

 .PHONY: dtc/all
 dtc/all: .git-submodule-status dtc/libfdt
 	$(call quiet-command,$(MAKE) $(DTC_MAKE_ARGS) CPPFLAGS="$(DTC_CPPFLAGS)" CFLAGS="$(DTC_CFLAGS)" LDFLAGS="$(QEMU_LDFLAGS)" ARFLAGS="$(ARFLAGS)" CC="$(CC)" AR="$(AR)" LD="$(LD)" $(SUBDIR_MAKEFLAGS) libfdt,)

 dtc/%: .git-submodule-status
 	@mkdir -p $@

 # Retain for a while so that incremental build across this patch
 # does not raise an error for missing target "capstone/all", which
 # comes from the saved SUBDIRS value.
 .PHONY: capstone/all
 capstone/all:

 .PHONY: slirp/all
 slirp/all: .git-submodule-status
 	$(call quiet-command,$(MAKE) -C $(SRC_PATH)/slirp		\
 		BUILD_DIR="$(BUILD_DIR)/slirp" 			\
 		PKG_CONFIG="$(PKG_CONFIG)" 				\
 		CC="$(CC)" AR="$(AR)" 	LD="$(LD)" RANLIB="$(RANLIB)"	\
 		CFLAGS="$(QEMU_CFLAGS) $(CFLAGS)" LDFLAGS="$(QEMU_LDFLAGS)")

 ROM_DIRS = $(addprefix pc-bios/, $(ROMS))
 ROM_DIRS_RULES=$(foreach t, all clean, $(addsuffix /$(t), $(ROM_DIRS)))
 # Only keep -O and -g cflags
 .PHONY: $(ROM_DIRS_RULES)
 $(ROM_DIRS_RULES):
 	$(call quiet-command,$(MAKE) $(SUBDIR_MAKEFLAGS) -C $(dir $@) V="$(V)" TARGET_DIR="$(dir $@)" $(notdir $@),)

 .PHONY: recurse-all recurse-clean
 recurse-all: $(addsuffix /all, $(ROM_DIRS))
 recurse-clean: $(addsuffix /clean, $(ROM_DIRS))

 ######################################################################

 clean: recurse-clean ninja-clean clean-ctlist
 	if test -f ninjatool; then ./ninjatool $(if $(V),-v,) -t clean; fi
 # avoid old build problems by removing potentially incorrect old files
 	rm -f config.mak op-i386.h opc-i386.h gen-op-i386.h op-arm.h opc-arm.h gen-op-arm.h
 	find . \( -name '*.so' -o -name '*.dll' -o -name '*.[oda]' \) -type f \
 		! -path ./roms/edk2/ArmPkg/Library/GccLto/liblto-aarch64.a \
 		! -path ./roms/edk2/ArmPkg/Library/GccLto/liblto-arm.a \
 		-exec rm {} +
 	rm -f TAGS cscope.* *.pod *~ */*~
 	rm -f fsdev/*.pod scsi/*.pod

 VERSION = $(shell cat $(SRC_PATH)/VERSION)

 dist: qemu-$(VERSION).tar.bz2

 qemu-%.tar.bz2:
 	$(SRC_PATH)/scripts/make-release "$(SRC_PATH)" "$(patsubst qemu-%.tar.bz2,%,$@)"

 distclean: clean ninja-distclean
 	-test -f ninjatool && ./ninjatool $(if $(V),-v,) -t clean -g
 	rm -f config-host.mak config-host.h*
 	rm -f tests/tcg/config-*.mak
 	rm -f config-all-disas.mak config.status
 	rm -f tests/qemu-iotests/common.env
 	rm -f roms/seabios/config.mak roms/vgabios/config.mak
 	rm -f qemu-plugins-ld.symbols qemu-plugins-ld64.symbols
 	rm -f *-config-target.h *-config-devices.mak *-config-devices.h
 	rm -rf meson-private meson-logs meson-info compile_commands.json
 	rm -f Makefile.ninja ninjatool ninjatool.stamp Makefile.mtest
 	rm -f config.log
 	rm -f linux-headers/asm
 	rm -Rf .sdk

 find-src-path = find "$(SRC_PATH)/" -path "$(SRC_PATH)/meson" -prune -o -name "*.[chsS]"

 .PHONY: ctags
 ctags:
 	rm -f tags
 	$(find-src-path) -exec ctags --append {} +

 .PHONY: TAGS
 TAGS:
 	rm -f TAGS
 	$(find-src-path) -exec etags --append {} +

 .PHONY: cscope
 cscope:
 	rm -f "$(SRC_PATH)"/cscope.*
 	$(find-src-path) -print | sed -e 's,^\./,,' > "$(SRC_PATH)/cscope.files"
 	cscope -b -i"$(SRC_PATH)/cscope.files"

 # Needed by "meson install"
 export DESTDIR

 include $(SRC_PATH)/tests/docker/Makefile.include
 include $(SRC_PATH)/tests/vm/Makefile.include

 print-help-run = printf "  %-30s - %s\\n" "$1" "$2"
 print-help = $(quiet-@)$(call print-help-run,$1,$2)

 .PHONY: help
 help:
 	@echo  'Generic targets:'
 	$(call print-help,all,Build all)
 	$(call print-help,dir/file.o,Build specified target only)
 	$(call print-help,install,Install QEMU, documentation and tools)
 	$(call print-help,ctags/TAGS,Generate tags file for editors)
 	$(call print-help,cscope,Generate cscope index)
 	$(call print-help,sparse,Run sparse on the QEMU source)
 	@echo  ''
 ifeq ($(CONFIG_PLUGIN),y)
 	@echo  'Plugin targets:'
 	$(call print-help,plugins,Build the example TCG plugins)
 	@echo  ''
 endif
 	@echo  'Cleaning targets:'
 	$(call print-help,clean,Remove most generated files but keep the config)
 	$(call print-help,distclean,Remove all generated files)
 	$(call print-help,dist,Build a distributable tarball)
 	@echo  ''
 	@echo  'Test targets:'
 	$(call print-help,check,Run all tests (check-help for details))
 	$(call print-help,bench,Run all benchmarks)
 	$(call print-help,docker,Help about targets running tests inside containers)
 	$(call print-help,vm-help,Help about targets running tests inside VM)
 	@echo  ''
 	@echo  'Documentation targets:'
 	$(call print-help,html man,Build documentation in specified format)
 	@echo  ''
 ifdef CONFIG_WIN32
 	@echo  'Windows targets:'
 	$(call print-help,installer,Build NSIS-based installer for QEMU)
 ifdef CONFIG_QGA_MSI
 	$(call print-help,msi,Build MSI-based installer for qemu-ga)
 endif
 	@echo  ''
 endif
 	$(call print-help,$(MAKE) [targets],(quiet build, default))
 	$(call print-help,$(MAKE) V=1 [targets],(verbose build))

 # will delete the target of a rule if commands exit with a nonzero exit status
 .DELETE_ON_ERROR:

 print-%:
 	@echo '$*=$($*)'
	# Makefile for QEMU.

	ifneq ($(words $(subst :, ,$(CURDIR))), 1)
	$(error main directory cannot contain spaces nor colons)
	endif

	# Always point to the root of the build tree (needs GNU make).
	BUILD_DIR=$(CURDIR)

	# Before including a proper config-host.mak, assume we are in the source tree
	SRC_PATH=.

	# Don't use implicit rules or variables
	# we have explicit rules for everything
	MAKEFLAGS += -rR

	# Usage: $(call quiet-command,command and args,"NAME","args to print")
	# This will run "command and args", and either:
	# if V=1 just print the whole command and args
	# otherwise print the 'quiet' output in the format " NAME args to print"
	# NAME should be a short name of the command, 7 letters or fewer.
	# If called with only a single argument, will print nothing in quiet mode.
	quiet-command-run = $(if $(V),,$(if $2,printf " %-7s %s\n" $2 $3 && ))$1
	quiet-@ = $(if $(V),,@)
	quiet-command = $(quiet-@)$(call quiet-command-run,$1,$2,$3)

	UNCHECKED_GOALS := %clean TAGS cscope ctags dist \
	help check-help print-% \
	docker docker-% vm-help vm-test vm-build-%

	# All following code might depend on configuration variables
	ifneq ($(wildcard config-host.mak),)
	# Put the all: rule here so that config-host.mak can contain dependencies.
	all:
	include config-host.mak

	git-submodule-update:

	.PHONY: git-submodule-update

	git_module_status := $(shell \
	cd '$(SRC_PATH)' && \
	GIT="$(GIT)" ./scripts/git-submodule.sh status $(GIT_SUBMODULES); \
	echo $$?; \
	)

	ifeq (1,$(git_module_status))
	ifeq (no,$(GIT_UPDATE))
	git-submodule-update:
	$(call quiet-command, \
	echo && \
	echo "GIT submodule checkout is out of date. Please run" && \
	echo " scripts/git-submodule.sh update $(GIT_SUBMODULES)" && \
	echo "from the source directory checkout $(SRC_PATH)" && \
	echo && \
	exit 1)
	else
	git-submodule-update:
	$(call quiet-command, \
	(cd $(SRC_PATH) && GIT="$(GIT)" ./scripts/git-submodule.sh update $(GIT_SUBMODULES)), \
	"GIT","$(GIT_SUBMODULES)")
	endif
	endif

	export NINJA=./ninjatool

	# Running meson regenerates both build.ninja and ninjatool, and that is
	# enough to prime the rest of the build.
	ninjatool: build.ninja

	Makefile.ninja: build.ninja ninjatool
	./ninjatool -t ninja2make --omit clean dist uninstall cscope TAGS ctags < $< > $@
	-include Makefile.ninja

	${ninja-targets-c_COMPILER} ${ninja-targets-cpp_COMPILER}: .var.command += -MP

	# If MESON is empty, the rule will be re-evaluated after Makefiles are
	# reread (and MESON won't be empty anymore).
	ifneq ($(MESON),)
	Makefile.mtest: build.ninja scripts/mtest2make.py
	$(MESON) introspect --targets --tests --benchmarks \| $(PYTHON) scripts/mtest2make.py > $@
	-include Makefile.mtest
	endif

	Makefile: .git-submodule-status
	.git-submodule-status: git-submodule-update config-host.mak

	# Check that we're not trying to do an out-of-tree build from
	# a tree that's been used for an in-tree build.
	ifneq ($(realpath $(SRC_PATH)),$(realpath .))
	ifneq ($(wildcard $(SRC_PATH)/config-host.mak),)
	$(error This is an out of tree build but your source tree ($(SRC_PATH)) \
	seems to have been used for an in-tree build. You can fix this by running \
	"$(MAKE) distclean && rm -rf -linux-user -softmmu" in your source tree)
	endif
	endif

	config-host.mak: $(SRC_PATH)/configure $(SRC_PATH)/pc-bios $(SRC_PATH)/VERSION
	@echo $@ is out-of-date, running configure
	@if test -f meson-private/coredata.dat; then \
	./config.status --skip-meson; \
	else \
	./config.status; \
	fi

	# Force configure to re-run if the API symbols are updated
	ifeq ($(CONFIG_PLUGIN),y)
	config-host.mak: $(SRC_PATH)/plugins/qemu-plugins.symbols

	.PHONY: plugins
	plugins:
	$(call quiet-command,\
	$(MAKE) $(SUBDIR_MAKEFLAGS) -C contrib/plugins V="$(V)", \
	"BUILD", "example plugins")
	endif

	else
	config-host.mak:
	ifneq ($(filter-out $(UNCHECKED_GOALS),$(MAKECMDGOALS)),$(if $(MAKECMDGOALS),,fail))
	@echo "Please call configure before running make!"
	@exit 1
	endif
	endif

	# Only needed in case Makefile.ninja does not exist.
	.PHONY: ninja-clean ninja-distclean clean-ctlist
	clean-ctlist:
	ninja-clean::
	ninja-distclean::
	build.ninja: config-host.mak

	# Don't try to regenerate Makefile or configure
	# We don't generate any of them
	Makefile: ;
	configure: ;

	.PHONY: all clean distclean install \
	recurse-all dist msi FORCE

	SUBDIR_MAKEFLAGS=$(if $(V),,--no-print-directory --quiet)

	include $(SRC_PATH)/tests/Makefile.include

	all: recurse-all
	Makefile: $(addsuffix /all, $(SUBDIRS))

	# LIBFDT_lib="": avoid breaking existing trees with objects requiring -fPIC
	DTC_MAKE_ARGS=-I$(SRC_PATH)/dtc VPATH=$(SRC_PATH)/dtc -C dtc V="$(V)" LIBFDT_lib=""
	DTC_CFLAGS=$(CFLAGS) $(QEMU_CFLAGS)
	DTC_CPPFLAGS=-I$(SRC_PATH)/dtc/libfdt

	.PHONY: dtc/all
	dtc/all: .git-submodule-status dtc/libfdt
	$(call quiet-command,$(MAKE) $(DTC_MAKE_ARGS) CPPFLAGS="$(DTC_CPPFLAGS)" CFLAGS="$(DTC_CFLAGS)" LDFLAGS="$(QEMU_LDFLAGS)" ARFLAGS="$(ARFLAGS)" CC="$(CC)" AR="$(AR)" LD="$(LD)" $(SUBDIR_MAKEFLAGS) libfdt,)

	dtc/%: .git-submodule-status
	@mkdir -p $@

	# Retain for a while so that incremental build across this patch
	# does not raise an error for missing target "capstone/all", which
	# comes from the saved SUBDIRS value.
	.PHONY: capstone/all
	capstone/all:

	.PHONY: slirp/all
	slirp/all: .git-submodule-status
	$(call quiet-command,$(MAKE) -C $(SRC_PATH)/slirp \
	BUILD_DIR="$(BUILD_DIR)/slirp" \
	PKG_CONFIG="$(PKG_CONFIG)" \
	CC="$(CC)" AR="$(AR)" LD="$(LD)" RANLIB="$(RANLIB)" \
	CFLAGS="$(QEMU_CFLAGS) $(CFLAGS)" LDFLAGS="$(QEMU_LDFLAGS)")

	ROM_DIRS = $(addprefix pc-bios/, $(ROMS))
	ROM_DIRS_RULES=$(foreach t, all clean, $(addsuffix /$(t), $(ROM_DIRS)))
	# Only keep -O and -g cflags
	.PHONY: $(ROM_DIRS_RULES)
	$(ROM_DIRS_RULES):
	$(call quiet-command,$(MAKE) $(SUBDIR_MAKEFLAGS) -C $(dir $@) V="$(V)" TARGET_DIR="$(dir $@)" $(notdir $@),)

	.PHONY: recurse-all recurse-clean
	recurse-all: $(addsuffix /all, $(ROM_DIRS))
	recurse-clean: $(addsuffix /clean, $(ROM_DIRS))

	######################################################################

	clean: recurse-clean ninja-clean clean-ctlist
	if test -f ninjatool; then ./ninjatool $(if $(V),-v,) -t clean; fi
	# avoid old build problems by removing potentially incorrect old files
	rm -f config.mak op-i386.h opc-i386.h gen-op-i386.h op-arm.h opc-arm.h gen-op-arm.h
	find . \( -name '.so' -o -name '.dll' -o -name '*.[oda]' \) -type f \
	! -path ./roms/edk2/ArmPkg/Library/GccLto/liblto-aarch64.a \
	! -path ./roms/edk2/ArmPkg/Library/GccLto/liblto-arm.a \
	-exec rm {} +
	rm -f TAGS cscope.* .pod ~ /~
	rm -f fsdev/.pod scsi/.pod

	VERSION = $(shell cat $(SRC_PATH)/VERSION)

	dist: qemu-$(VERSION).tar.bz2

	qemu-%.tar.bz2:
	$(SRC_PATH)/scripts/make-release "$(SRC_PATH)" "$(patsubst qemu-%.tar.bz2,%,$@)"

	distclean: clean ninja-distclean
	-test -f ninjatool && ./ninjatool $(if $(V),-v,) -t clean -g
	rm -f config-host.mak config-host.h*
	rm -f tests/tcg/config-*.mak
	rm -f config-all-disas.mak config.status
	rm -f tests/qemu-iotests/common.env
	rm -f roms/seabios/config.mak roms/vgabios/config.mak
	rm -f qemu-plugins-ld.symbols qemu-plugins-ld64.symbols
	rm -f -config-target.h -config-devices.mak *-config-devices.h
	rm -rf meson-private meson-logs meson-info compile_commands.json
	rm -f Makefile.ninja ninjatool ninjatool.stamp Makefile.mtest
	rm -f config.log
	rm -f linux-headers/asm
	rm -Rf .sdk

	find-src-path = find "$(SRC_PATH)/" -path "$(SRC_PATH)/meson" -prune -o -name "*.[chsS]"

	.PHONY: ctags
	ctags:
	rm -f tags
	$(find-src-path) -exec ctags --append {} +

	.PHONY: TAGS
	TAGS:
	rm -f TAGS
	$(find-src-path) -exec etags --append {} +

	.PHONY: cscope
	cscope:
	rm -f "$(SRC_PATH)"/cscope.*
	$(find-src-path) -print \| sed -e 's,^\./,,' > "$(SRC_PATH)/cscope.files"
	cscope -b -i"$(SRC_PATH)/cscope.files"

	# Needed by "meson install"
	export DESTDIR

	include $(SRC_PATH)/tests/docker/Makefile.include
	include $(SRC_PATH)/tests/vm/Makefile.include

	print-help-run = printf " %-30s - %s\\n" "$1" "$2"
	print-help = $(quiet-@)$(call print-help-run,$1,$2)

	.PHONY: help
	help:
	@echo 'Generic targets:'
	$(call print-help,all,Build all)
	$(call print-help,dir/file.o,Build specified target only)
	$(call print-help,install,Install QEMU, documentation and tools)
	$(call print-help,ctags/TAGS,Generate tags file for editors)
	$(call print-help,cscope,Generate cscope index)
	$(call print-help,sparse,Run sparse on the QEMU source)
	@echo ''
	ifeq ($(CONFIG_PLUGIN),y)
	@echo 'Plugin targets:'
	$(call print-help,plugins,Build the example TCG plugins)
	@echo ''
	endif
	@echo 'Cleaning targets:'
	$(call print-help,clean,Remove most generated files but keep the config)
	$(call print-help,distclean,Remove all generated files)
	$(call print-help,dist,Build a distributable tarball)
	@echo ''
	@echo 'Test targets:'
	$(call print-help,check,Run all tests (check-help for details))
	$(call print-help,bench,Run all benchmarks)
	$(call print-help,docker,Help about targets running tests inside containers)
	$(call print-help,vm-help,Help about targets running tests inside VM)
	@echo ''
	@echo 'Documentation targets:'
	$(call print-help,html man,Build documentation in specified format)
	@echo ''
	ifdef CONFIG_WIN32
	@echo 'Windows targets:'
	$(call print-help,installer,Build NSIS-based installer for QEMU)
	ifdef CONFIG_QGA_MSI
	$(call print-help,msi,Build MSI-based installer for qemu-ga)
	endif
	@echo ''
	endif
	$(call print-help,$(MAKE) [targets],(quiet build, default))
	$(call print-help,$(MAKE) V=1 [targets],(verbose build))

	# will delete the target of a rule if commands exit with a nonzero exit status
	.DELETE_ON_ERROR:

	print-%:
	@echo '$=$($)'