diff --git a/src/Makefile b/src/Makefile
index 5ad8a2e..89f740f 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -23,8 +23,8 @@ OBJECTS = $(subst .cpp,.o,$(SOURCES))
 all: $(OBJECTS) tinyxml
 	$(CC) -o antigrav $(OBJECTS) tinyxml/libtinyxml.a $(LDFLAGS)
 
-$(OBJECTS): %.o:
-	$(CC) -c $(CFLAGS) $(subst .o,.cpp,$@) -o $@
+$(OBJECTS): %.o: %.cpp
+	$(CC) -c $(CFLAGS) $< -o $@
 
 tinyxml:
 	$(MAKE) -C tinyxml
diff --git a/src/tinyxml/Makefile b/src/tinyxml/Makefile
index 53a894c..a74f0a3 100644
--- a/src/tinyxml/Makefile
+++ b/src/tinyxml/Makefile
@@ -15,8 +15,8 @@ all: $(TARGET)
 $(TARGET): $(OBJECTS)
 	ar crs $(TARGET) $(OBJECTS)
 
-$(OBJECTS): %.o:
-	$(CC) -c $(CFLAGS) $(subst .o,.cpp,$@) -o $@
+$(OBJECTS): %.o: %.cpp
+	$(CC) -c $(CFLAGS) $< -o $@
 
 clean:
 	rm -f *.o