Allow finer control over how product variables are inherited.

$(foreach p,$(PRODUCTS),$(call dump-product,$(p)))

endef

#

# Internal function. Appends inherited product variables to an existing one.

#

# $(1): Product variable to operate on

# $(2): Value to append

#

define inherit-product_append-var

  $(eval $(1) := $($(1)) $(INHERIT_TAG)$(strip $(2)))

endef

#

# Internal function. Prepends inherited product variables to an existing one.

#

# $(1): Product variable to operate on

# $(2): Value to prepend

#

define inherit-product_prepend-var

  $(eval $(1) := $(INHERIT_TAG)$(strip $(2)) $($(1)))

endef

#

# Internal function. Tracks visited notes during inheritance resolution.

#

# $(1): Product being inherited

#

define inherit-product_track-node

  $(eval inherit_var := \

      PRODUCTS.$(strip $(word 1,$(_include_stack))).INHERITS_FROM) \

  $(eval $(inherit_var) := $(sort $($(inherit_var)) $(strip $(1)))) \

  $(eval inherit_var:=) \

  $(eval ALL_PRODUCTS := $(sort $(ALL_PRODUCTS) $(word 1,$(_include_stack))))

endef

#

# $(1): product to inherit

#

# Does three things:

#  1. Inherits all of the variables from $1.

#  1. Inherits all of the variables from $1, prioritizing existing settings.

#  2. Records the inheritance in the .INHERITS_FROM variable

#  3. Records that we've visited this node, in ALL_PRODUCTS

#

define inherit-product

  $(foreach v,$(_product_var_list), \

      $(eval $(v) := $($(v)) $(INHERIT_TAG)$(strip $(1)))) \

  $(eval inherit_var := \

      PRODUCTS.$(strip $(word 1,$(_include_stack))).INHERITS_FROM) \

  $(eval $(inherit_var) := $(sort $($(inherit_var)) $(strip $(1)))) \

  $(eval inherit_var:=) \

  $(eval ALL_PRODUCTS := $(sort $(ALL_PRODUCTS) $(word 1,$(_include_stack))))

      $(call inherit-product_append-var,$(v),$(1))) \

  $(call inherit-product_track-node,$(1))

endef

#

# $(1): product to inherit

#

# Does three things:

#  1. Inherits all of the variables from $1, prioritizing inherited settings.

#  2. Records the inheritance in the .INHERITS_FROM variable

#  3. Records that we've visited this node, in ALL_PRODUCTS

#

define prepend-product

  $(foreach v,$(_product_var_list), \

      $(call inherit-product_prepend-var,$(v),$(1))) \

  $(call inherit-product_track-node,$(1))

endef

#

# Do inherit-product only if $(1) exists

  $(if $(wildcard $(1)),$(call inherit-product,$(1)),)

endef

#

# Do inherit-product-prepend only if $(1) exists

#

define prepend-product-if-exists

  $(if $(wildcard $(1)),$(call prepend-product,$(1)),)

endef

#

# $(1): product makefile list

#