-i3_SOURCES_GENERATED = src/cfgparse.tab.c src/cfgparse.yy.c
-i3_SOURCES := $(filter-out $(i3_SOURCES_GENERATED),$(wildcard src/*.c))
+i3_SOURCES_GENERATED = src/cfgparse.tab.c src/cfgparse.yy.c
+i3_SOURCES := $(filter-out $(i3_SOURCES_GENERATED),$(wildcard src/*.c))