1
 2foo = f-ok
 3bar = b-ok
 4
 5FOO = foo
 6F = f
 7
 8BAR = bar
 9B = b
10
11export $(FOO)
12export $(B)ar
13
14.RECIPEPREFIX := >
15all:
16> @echo foo=$(foo) bar=$(bar)
17> @echo foo=$$foo bar=$$bar