1MAKEVER:=$(shell make --version | ruby -n0e 'puts $$_[/Make (\d)/,1]') 2 3ifeq ($(MAKEVER),4) 4# A variable name with space is invalid on GNU make 4. 5all: 6 echo PASS 7else 8varname_with_ws:=hello, world! 9$(varname_with_ws):=PASS 10foo bar = PASS2 11all: 12 echo $(hello, world!) 13 echo $(foo bar) 14endif 15