ifeq "{xxx}" "xxx"
MAKE_USED = dmake
endif

ifneq "$(.VARIABLES)" ""
MAKE_USED = gnumake
endif

#if... How can nmake be identified?
#MAKE_USED = nmake
#endif

##</code><code>##

NORL =@# No Output of Recipe Line
.PHONY: check_used_make_program

check_used_make_program:
ifeq "$(MAKE_USED)" "gnumake"
	$(NORL)$(error ERROR: Using $(MAKE_USED) for a Makefile intended for ?make)
endif

##</code><code>##

ifeq "$(MAKE_USED)" "dmake"
#               The message is NOT sent to STDERR
	$(NORL)echo ERROR: Using $(MAKE_USED) for a Makefile intended for ?make
	$(assign ERR OR = ERROR) #Generates an error message
endif