# - If the content differ the new file is used
# - If they are equal no change, and no timestamp update
define filechk
+ $(check-FORCE)
$(Q)set -e; \
mkdir -p $(dir $@); \
trap "rm -f $(dot-target).tmp" EXIT; \
# PHONY targets skipped in both cases.
newer-prereqs = $(filter-out $(PHONY),$?)
+# It is a typical mistake to forget the FORCE prerequisite. Check it here so
+# no more breakage will slip in.
+check-FORCE = $(if $(filter FORCE, $^),,$(warning FORCE prerequisite is missing))
+
+if-changed-cond = $(newer-prereqs)$(cmd-check)$(check-FORCE)
+
# Execute command if command has changed or prerequisite(s) are updated.
-if_changed = $(if $(newer-prereqs)$(cmd-check), \
+if_changed = $(if $(if-changed-cond), \
$(cmd); \
printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:)
# Execute the command and also postprocess generated .d dependencies file.
-if_changed_dep = $(if $(newer-prereqs)$(cmd-check),$(cmd_and_fixdep),@:)
+if_changed_dep = $(if $(if-changed-cond),$(cmd_and_fixdep),@:)
cmd_and_fixdep = \
$(cmd); \
# Usage: $(call if_changed_rule,foo)
# Will check if $(cmd_foo) or any of the prerequisites changed,
# and if so will execute $(rule_foo).
-if_changed_rule = $(if $(newer-prereqs)$(cmd-check),$(rule_$(1)),@:)
+if_changed_rule = $(if $(if-changed-cond),$(rule_$(1)),@:)
###
# why - tell why a target got built