1
 2.WARNINGS = undefined-var
 3vars := $(.VARIABLES) $(MAKECMDGOALS) $(MAKE_RESTARTS) $(CURDIR)
 4vars += $(GNUMAKEFLAGS) $(MAKEFLAGS) $(MFLAGS) $(MAKE_COMMAND) $(MAKE)
 5vars += $(MAKEFILE_LIST) $(MAKEOVERRIDES) $(-*-command-variables-*-)
 6vars += $(.RECIPEPREFIX) $(.LOADED) $(.FEATURES)
 7vars += $(SHELL) $(.SHELLFLAGS) $(MAKE_TERMOUT) $(MAKE_TERMERR)
 8vars += $(.DEFAULT) $(.DEFAULT_GOAL) $(-*-eval-flags-*-) $(SUFFIXES)
 9vars += $(VPATH) $(GPATH)
10all:;