diff --git a/src/macosx/SerialPortMACOSX.hxx b/src/macosx/SerialPortMACOSX.hxx
index 91f8b8547..052db7982 100644
--- a/src/macosx/SerialPortMACOSX.hxx
+++ b/src/macosx/SerialPortMACOSX.hxx
@@ -41,12 +41,12 @@ class SerialPortMACOSX : public SerialPort
       @param device  The name of the port
       @return  False on any errors, else true
     */
-    bool openPort(const string& device);
+    bool openPort(const string& device) override;
 
     /**
       Close a previously opened serial port.
     */
-    void closePort();
+    void closePort() override;
 
     /**
       Write a byte to the serial port.
@@ -54,7 +54,7 @@ class SerialPortMACOSX : public SerialPort
       @param data  The byte to write to the port
       @return  True if a byte was written, else false
     */
-    bool writeByte(const uInt8* data);
+    bool writeByte(const uInt8* data) override;
 
   private:
     // File descriptor for serial connection
diff --git a/src/macosx/stella.xcodeproj/project.pbxproj b/src/macosx/stella.xcodeproj/project.pbxproj
index 6848be80b..a9d3bfb08 100644
--- a/src/macosx/stella.xcodeproj/project.pbxproj
+++ b/src/macosx/stella.xcodeproj/project.pbxproj
@@ -2044,7 +2044,7 @@
 		29B97313FDCFA39411CA2CEA /* Project object */ = {
 			isa = PBXProject;
 			attributes = {
-				LastUpgradeCheck = 0620;
+				LastUpgradeCheck = 0630;
 				ORGANIZATIONNAME = net.sourceforge.stella;
 			};
 			buildConfigurationList = 2D91752109BA903B0026E9FF /* Build configuration list for PBXProject "stella" */;
@@ -2509,10 +2509,13 @@
 					.,
 					"$(HOME)/Library/Frameworks",
 				);
+				GCC_ENABLE_CPP_RTTI = NO;
 				GCC_OPTIMIZATION_LEVEL = 0;
 				GCC_VERSION = "";
 				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
 				GCC_WARN_ABOUT_RETURN_TYPE = YES;
+				GCC_WARN_HIDDEN_VIRTUAL_FUNCTIONS = YES;
+				GCC_WARN_NON_VIRTUAL_DESTRUCTOR = YES;
 				GCC_WARN_UNDECLARED_SELECTOR = YES;
 				GCC_WARN_UNINITIALIZED_AUTOS = YES;
 				GCC_WARN_UNUSED_FUNCTION = YES;
@@ -2522,6 +2525,7 @@
 				MACOSX_DEPLOYMENT_TARGET = 10.7;
 				SDKROOT = macosx;
 				VALID_ARCHS = x86_64;
+				WARNING_CFLAGS = "-Wall";
 			};
 			name = Development;
 		};
@@ -2545,6 +2549,8 @@
 				GCC_VERSION = "";
 				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
 				GCC_WARN_ABOUT_RETURN_TYPE = YES;
+				GCC_WARN_HIDDEN_VIRTUAL_FUNCTIONS = YES;
+				GCC_WARN_NON_VIRTUAL_DESTRUCTOR = YES;
 				GCC_WARN_UNDECLARED_SELECTOR = YES;
 				GCC_WARN_UNINITIALIZED_AUTOS = YES;
 				GCC_WARN_UNUSED_FUNCTION = YES;
@@ -2554,6 +2560,7 @@
 				MACOSX_DEPLOYMENT_TARGET = 10.7;
 				SDKROOT = macosx;
 				VALID_ARCHS = x86_64;
+				WARNING_CFLAGS = "-Wall";
 			};
 			name = Deployment;
 		};
@@ -2570,9 +2577,12 @@
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				DEBUG_INFORMATION_FORMAT = dwarf;
 				FRAMEWORK_SEARCH_PATHS = /Library/Frameworks;
+				GCC_ENABLE_CPP_RTTI = NO;
 				GCC_VERSION = "";
 				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
 				GCC_WARN_ABOUT_RETURN_TYPE = YES;
+				GCC_WARN_HIDDEN_VIRTUAL_FUNCTIONS = YES;
+				GCC_WARN_NON_VIRTUAL_DESTRUCTOR = YES;
 				GCC_WARN_UNDECLARED_SELECTOR = YES;
 				GCC_WARN_UNINITIALIZED_AUTOS = YES;
 				GCC_WARN_UNUSED_FUNCTION = YES;
@@ -2582,6 +2592,7 @@
 				MACOSX_DEPLOYMENT_TARGET = 10.7;
 				SDKROOT = macosx;
 				VALID_ARCHS = x86_64;
+				WARNING_CFLAGS = "-Wall";
 			};
 			name = Default;
 		};