move main to a new source file, update makefile to support multiple sources

neotools/neoadpcmextract.Makefile

@@ -1,12 +1,23 @@
 TARGET := neoadpcmextract
-SOURCE := neoadpcmextract.c
+SOURCE := autoextract.c neoadpcmextract.c
 CFLAGS := -std=c99 -O2 -pipe -Wall -Wextra -pedantic
+LDFLAGS := $(CFLAGS)
 
+
+OBJECT := $(SOURCE:%.c=%.o)
+DEPEND := $(OBJECT:%.o=%.d)
+
+.PHONY: default all clean
+default: $(TARGET)
 all: $(TARGET)
 
-$(TARGET): $(SOURCE)
-	$(CC) $(CFLAGS) $< -o $@
+$(TARGET): $(OBJECT)
+	$(CC) $(LDFLAGS) $^ -o $@
+
+%.o: %.c
+	$(CC) $(CFLAGS) -MMD -c $< -o $@
+
+-include: $(DEPEND)
 
-.PHONY: clean
 clean:
-	rm -f $(TARGET)
+	rm -f $(TARGET) $(OBJECT) $(DEPEND)