1ifdef WARNING1
 2$(warning warning is $(WARNING1))
 3endif
 4
 5ifdef WARNING2
 6$(warning warning is $(WARNING2))
 7endif
 8
 9ifdef WARNING3
10all: some; @echo hi $(warning warning is $(WARNING3))
11endif
12
13ifdef WARNING4
14all: some; @echo hi
15	@echo there $(warning warning is $(WARNING4))
16endif
17
18some: ; @echo Some stuff