kbuild: make -r/-R effective in top Makefile for old Make versions

PHONY := _all

_all:

# Do not use make's built-in rules and variables

# (this increases performance and avoids hard-to-debug behaviour)

MAKEFLAGS += -rR

# Avoid funny character set dependencies

unexport LC_ALL

LC_COLLATE=C

LC_NUMERIC=C

export LC_COLLATE LC_NUMERIC

# Avoid interference with shell env settings

unexport GREP_OPTIONS

# We are using a recursive build, so we need to do a little thinking

# to get the ordering right.

#

# descending is started. They are now explicitly listed as the

# prepare rule.

ifneq ($(sub-make-done),1)

# Do not use make's built-in rules and variables

# (this increases performance and avoids hard-to-debug behaviour)

MAKEFLAGS += -rR

# Avoid funny character set dependencies

unexport LC_ALL

LC_COLLATE=C

LC_NUMERIC=C

export LC_COLLATE LC_NUMERIC

# Avoid interference with shell env settings

unexport GREP_OPTIONS

# Beautify output

# ---------------------------------------------------------------------------

#

# KBUILD_SRC is not intended to be used by the regular user (for now),

# it is set on invocation of make with KBUILD_OUTPUT or O= specified.

ifeq ($(KBUILD_SRC),)

# OK, Make called in directory where kernel src resides

# Do we want to locate output files in a separate directory?

# 'sub-make' below.

MAKEFLAGS += --include-dir=$(CURDIR)

else

# Do not print "Entering directory ..." at all for in-tree build.

MAKEFLAGS += --no-print-directory

endif # ifneq ($(KBUILD_OUTPUT),)

PHONY += $(MAKECMDGOALS) sub-make

$(filter-out _all sub-make $(CURDIR)/Makefile, $(MAKECMDGOALS)) _all: sub-make

# Invoke a second make in the output directory, passing relevant variables

sub-make:

	$(Q)$(MAKE) -C $(KBUILD_OUTPUT) KBUILD_SRC=$(CURDIR) \

	$(Q)$(MAKE) sub-make-done=1 \

	$(if $(KBUILD_OUTPUT),-C $(KBUILD_OUTPUT) KBUILD_SRC=$(CURDIR)) \

	-f $(CURDIR)/Makefile $(filter-out _all sub-make,$(MAKECMDGOALS))

# Leave processing to above invocation of make

skip-makefile := 1

endif # ifneq ($(KBUILD_OUTPUT),)

endif # ifeq ($(KBUILD_SRC),)

else # sub-make-done

# We process the rest of the Makefile if this is the final invocation of make

ifeq ($(skip-makefile),)

# Do not print "Entering directory ...",

# but we want to display it when entering to the output directory

endif   # ifeq ($(config-targets),1)

endif   # ifeq ($(mixed-targets),1)

endif	# skip-makefile

endif   # sub-make-done

PHONY += FORCE

FORCE: