target variable doesn't work in ifeq?

[cbrown]

if I have this simple makefile, the output of make is "all is not all",

.PHONY: all artifact

all: FLG:=all
all: artifact

artifact:
ifeq ($(strip $(FLG)),all)
        echo $(strip $(FLG)) is all
else
        echo $(strip $(FLG)) is not all
endif


Which is confusing because the variable obviously is set to the expected
value.  Is this a bug, or am I missing some nuance in the manual?

--CB