Fix Makefile

- Compile with CXX, as this is c++ code
- Don't override user-set CXX
- Place DATADIR define to CXXFLAGS where it belongs

Makefile

@@ -9,10 +9,10 @@ BINDIR=bin/
 
 #append -DWITH_WIIUSE to compile with WIIUSE support!
 #append -DNOSOUND to compile WITHOUT sound support
-CC=g++ -DDATADIR="\"$(DATADIR)\""
 STRIP=strip
+CXX?=g++
 
-CFLAGS+=-c -Wall `sdl-config --cflags`
+CXXFLAGS+=-Wall `sdl-config --cflags` -DDATADIR="\"$(DATADIR)\""
 
 #append -lwiiuse to compile with WIIUSE support
 #remove -lSDL_mixer if compiling with -DNOSOUND
@@ -26,11 +26,11 @@ EXECUTABLE=sdl-ball
 all: $(SOURCES) $(EXECUTABLE)
 
 $(EXECUTABLE): $(OBJECTS)
-	$(CC) $(LDFLAGS) $(OBJECTS) $(LIBS) -o $@
+	$(CXX) $(LDFLAGS) $(OBJECTS) $(LIBS) -o $@
 	$(STRIP) $@
 
 .cpp.o:
-	$(CC) $(CFLAGS) $< -o $@
+	$(CXX) -c $(CXXFLAGS) $< -o $@
 
 clean:
 	rm -f *.o sdl-ball