-PROG = lackey
-PROG_SRC = main screen date event util
-TEST = test
-TEST_SRC = test date util
-VIEWS = day week month year todo notes settings help
-CALS = dummy ical
+PROG ?= lackey
+PROG_SRC ?= main view date cal util
+TEST ?= test
+TEST_SRC ?= test date util
+VIEWS ?= day week month year events todo settings help
+CALS ?= dummy ical