The geos-apple target will build that library if it doesn't exist.
../wrk/$(TARGET)/convert.o: $(SRCDIR)/targetutil/convert.c | ../wrk/$(TARGET)
$(COMPILE_recipe)
-../targetutil/convert.system: ../wrk/$(TARGET)/convert.o | ../targetutil
- $(LD) -o $@ -C apple2enh-system.cfg $^ apple2enh.lib
+../lib/apple2enh.lib:
+ @$(MAKE) --no-print-directory apple2enh
+
+../targetutil/convert.system: ../wrk/$(TARGET)/convert.o ../lib/apple2enh.lib | ../targetutil
+ $(LD) -o $@ -C apple2enh-system.cfg $^
$(TARGET): ../targetutil/convert.system