Simplify (?) Makefile

Rename `main.c' to `baps1.c' to allow use of more implicit make rules.

src/Makefile

@@ -1,14 +1,9 @@
-CC		= cc -Wall -Wextra
 INST_PATH = /usr/local/bin
+OBJS = baps1.o timediff.o
+CFLAGS = -Wall -Wextra
+LDFLAGS = -lm
 
-baps1: main.o timediff.o
-	$(CC) -o baps1 main.o timediff.o -lm
-
-main.o: main.c
-	$(CC) -c main.c
-
-timediff.o: timediff.c
-	$(CC) -c timediff.c
+baps1: $(OBJS)
 
 install: baps1
 	install baps1 $(INST_PATH)/baps1
@@ -16,5 +11,6 @@ install: baps1
 uninstall:
 	rm $(INST_PATH)/baps1
 
+.PHONY: clean
 clean:
-	rm baps1 *.o
+	rm baps1 $(OBJS)