Adjust makefile to build individual modules

Author: dkl

.gitignore

@@ -3,3 +3,4 @@
 /tests/run
 /tests/run.exe
 config.mk
+/obj/*.o

makefile

@@ -5,19 +5,37 @@ prefix := /usr/local
 
 -include config.mk
 
+ALLFBCFLAGS := -m fbfrog -maxerr 1 $(FBFLAGS)
+ALLFBLFLAGS := $(FBFLAGS)
+
+SOURCES := $(sort $(wildcard *.bas))
+HEADERS := $(wildcard *.bi)
+OBJECTS := $(patsubst %.bas,obj/%.o,$(SOURCES))
+
+# We don't want to use any of make's built-in suffixes/rules
+.SUFFIXES:
+
+ifndef V
+  QUIET_FBC     = @echo "FBC $<";
+  QUIET_FBCLINK = @echo "FBCLINK $@";
+endif
+
 build: $(FBFROG) $(TESTSRUN)
 
-$(FBFROG): $(wildcard *.bas *.bi)
-	$(FBC) *.bas -m fbfrog -maxerr 1 $(FBFLAGS)
+$(FBFROG): $(OBJECTS)
+	$(QUIET_FBCLINK)$(FBC) $(ALLFBLFLAGS) $^ -x $@
+
+$(OBJECTS): obj/%.o: %.bas $(HEADERS)
+	$(QUIET_FBC)$(FBC) $(ALLFBCFLAGS) $< -c -o $@
 
 $(TESTSRUN): tests/run.bas util-path.bas util-str.bas
-	$(FBC) $< $(FBFLAGS)
+	$(QUIET_FBCLINK)$(FBC) $< $(FBFLAGS)
 
 tests: build
 	$(TESTSRUN)
 
 clean:
-	rm -f $(FBFROG) $(TESTSRUN)
+	rm -f $(FBFROG) $(TESTSRUN) obj/*.o
 
 install:
 	install $(FBFROG) "$(prefix)/bin"