build/bool.mk

   1 # Several "GNU make" functions to evaluate boolean expressions.  Valid
   2 # boolean values "y" (true) and "n" (false).
   3
   4 # Internal helper function: convert "y"/"n" to "y" / empty string.
   5 bool_is_true = $(filter y,$(1))
   6
   7 # $(call bool_not,$(a))
   8 bool_not = $(if $(call bool_is_true,$(1)),n,y)
   9
  10 # $(call bool_or,$(a),$(b))
  11 bool_or = $(if $(or $(call bool_is_true,$(1)),$(call bool_is_true,$(2))),y,n)
  12
  13 # $(call bool_and,$(a),$(b))
  14 bool_and = $(if $(and $(call bool_is_true,$(1)),$(call bool_is_true,$(2))),y,n)