Merge pull request #270 from jothan/Marlin_v1

Create an explicit rule for building applet/Marlin.cpp.

Marlin/Makefile

@@ -277,6 +277,10 @@ applet/%.o: %.c Configuration.h Configuration_adv.h $(MAKEFILE)
 	$(Pecho) "  CC    $@"
 	$P $(CC) -MMD -c $(ALL_CFLAGS) $< -o $@
 
+applet/%.o: applet/%.cpp Configuration.h Configuration_adv.h $(MAKEFILE)
+	$(Pecho) "  CXX   $@"
+	$P $(CXX) -MMD -c $(ALL_CXXFLAGS) $< -o $@
+
 applet/%.o: %.cpp Configuration.h Configuration_adv.h $(MAKEFILE)
 	$(Pecho) "  CXX   $@"
 	$P $(CXX) -MMD -c $(ALL_CXXFLAGS) $< -o $@