\ # " " ' ' ` ` [$]+[<>@?*{\(a-zA-Z0-9_][}\)a-zA-Z0-9_]* ^[ \t]*[a-zA-Z_][a-zA-Z0-9_]*[ \t]*\= define else endef endif ifdef ifeq ifndef ifneq override unexport addprefix addsuffix basename call dir error filter filter-out findstring firstword foreach join notdir origin patsubst shell sort strip subst suffix warning wildcard word words ^[ \t]*([a-zA-Z0-9_\.\-]+)[ \t]*\: \.DEFAULT \.EXPORT_ALL_VARIABLES \.IGNORE \.PHONY \.PRECIOUS \.SILENT \.SUFFIXES