+define Require/gnu-find
+ $(FIND) --version 2>/dev/null
+endef
+
+$(eval $(call Require,gnu-find, \
+ Please install GNU find \
+))
+
+define Require/getopt-extended
+ getopt --long - - >/dev/null
+endef
+
+$(eval $(call Require,getopt-extended, \
+ Please install an extended getopt version that supports --long \
+))