diff --git a/src/posix/cocoa/i_main.mm b/src/posix/cocoa/i_main.mm
index 851e72e48..0d426caaa 100644
--- a/src/posix/cocoa/i_main.mm
+++ b/src/posix/cocoa/i_main.mm
@@ -173,7 +173,9 @@ static void I_DetectOS()
 		"Unknown";
 #endif
 	
-	Printf("OS: %s %d.%d.%d (%s) %s\n", name, majorVersion, minorVersion, bugFixVersion, release, architecture);
+	Printf("OS: %s %d.%d.%d (%s) %s\n", name, 
+		int(majorVersion), int(minorVersion), int(bugFixVersion),
+		release, architecture);
 }
 
 
diff --git a/src/scripting/backend/codegen.cpp b/src/scripting/backend/codegen.cpp
index dc904b804..0ea6517da 100644
--- a/src/scripting/backend/codegen.cpp
+++ b/src/scripting/backend/codegen.cpp
@@ -8815,7 +8815,8 @@ ExpEmit FxVMFunctionCall::Emit(VMFunctionBuilder *build)
 			if (outerside == FScopeBarrier::Side_Virtual)
 				outerside = FScopeBarrier::SideFromObjectFlags(CallingFunction->OwningClass->ObjectFlags);
 
-			if (selfside != outerside && (selfside == FScopeBarrier::Side_Play || selfside == FScopeBarrier::Side_UI))	// if the self pointer and the calling functions have the same scope the check here is not needed.
+			// [ZZ] only emit if target side cannot be checked at compile time.
+			if (selfside == FScopeBarrier::Side_PlainData)
 			{
 				// Check the self object against the calling function's flags at run time
 				build->Emit(OP_SCOPE, selfemit.RegNum, outerside + 1, build->GetConstantAddress(vmfunc, ATAG_OBJECT));
diff --git a/src/scripting/decorate/thingdef_parse.cpp b/src/scripting/decorate/thingdef_parse.cpp
index 05a927288..7ccc0b7d7 100644
--- a/src/scripting/decorate/thingdef_parse.cpp
+++ b/src/scripting/decorate/thingdef_parse.cpp
@@ -97,6 +97,13 @@ PClassActor *DecoDerivedClass(const FScriptPosition &sc, PClassActor *parent, FN
 			sc.Message(MSG_FATAL, "Tried to define class '%s' more than twice in the same file.", typeName.GetChars());
 		}
 	}
+	
+	if (type != nullptr)
+	{
+		// [ZZ] DECORATE classes are always play
+		type->ObjectFlags = FScopeBarrier::ChangeSideInObjectFlags(type->ObjectFlags, FScopeBarrier::Side_Play);
+	}
+
 	return type;
 }
 
diff --git a/src/scripting/vm/vmexec.h b/src/scripting/vm/vmexec.h
index b588d15d3..900d06ffa 100644
--- a/src/scripting/vm/vmexec.h
+++ b/src/scripting/vm/vmexec.h
@@ -648,10 +648,10 @@ begin:
 			reg.a[a] = p->Virtuals[C];
 		}
 		NEXTOP;
-	OP(SCOPE) :
-	{
-		ASSERTA(a); ASSERTA(C);
-		FScopeBarrier::ValidateCall(((DObject*)konsta[a].v)->GetClass(), (VMFunction*)konsta[C].v, B - 1);
+	OP(SCOPE):
+		{
+			ASSERTA(a); ASSERTKA(C);
+			FScopeBarrier::ValidateCall(((DObject*)reg.a[a])->GetClass(), (VMFunction*)konsta[C].v, B - 1);
 		}
 		NEXTOP;
 
diff --git a/src/scripting/zscript/zcc_compile.cpp b/src/scripting/zscript/zcc_compile.cpp
index 222c20a26..f18c3230f 100644
--- a/src/scripting/zscript/zcc_compile.cpp
+++ b/src/scripting/zscript/zcc_compile.cpp
@@ -658,12 +658,12 @@ void ZCCCompiler::CreateClassTypes()
 						{
 							Error(c->cls, "Can't change class scope in class %s", c->NodeName().GetChars());
 						}
-						c->Type()->ObjectFlags = (c->Type()->ObjectFlags & ~(OF_UI | OF_Play)) | (parent->ObjectFlags & (OF_UI | OF_Play));
+						c->Type()->ObjectFlags = FScopeBarrier::ChangeSideInObjectFlags(c->Type()->ObjectFlags, FScopeBarrier::SideFromObjectFlags(parent->ObjectFlags));
 					}
 				}
 				else
 				{
-					c->Type()->ObjectFlags = (c->Type()->ObjectFlags&~OF_UI) | OF_Play;
+					c->Type()->ObjectFlags = FScopeBarrier::ChangeSideInObjectFlags(c->Type()->ObjectFlags, FScopeBarrier::Side_Play);
 				}
 
 				c->Type()->bExported = true;	// this class is accessible to script side type casts. (The reason for this flag is that types like PInt need to be skipped.)
diff --git a/src/sound/music_audiotoolbox_mididevice.cpp b/src/sound/music_audiotoolbox_mididevice.cpp
index 3dc57fdb0..ba48055e5 100644
--- a/src/sound/music_audiotoolbox_mididevice.cpp
+++ b/src/sound/music_audiotoolbox_mididevice.cpp
@@ -35,7 +35,7 @@
 	{                                                              \
 		DPrintf(DMSG_ERROR,                                        \
 			"Failed with error 0x%08X at " __FILE__ ":%d:\n> %s",  \
-			result, __LINE__, #CALL);                              \
+			int(result), __LINE__, #CALL);                         \
 		return __VA_ARGS__;                                        \
 	}                                                              \
 }
@@ -55,7 +55,7 @@ int AudioToolboxMIDIDevice::Open(void (*callback)(unsigned int, void *, DWORD, D
 		return 1;
 	}
 
-	CFRunLoopAddTimer(CFRunLoopGetMain(), m_timer, kCFRunLoopDefaultMode);
+	CFRunLoopAddTimer(CFRunLoopGetCurrent(), m_timer, kCFRunLoopDefaultMode);
 
 	m_callback = callback;
 	m_userData = userData;
@@ -73,7 +73,7 @@ void AudioToolboxMIDIDevice::Close()
 
 	if (nullptr != m_timer)
 	{
-		CFRunLoopRemoveTimer(CFRunLoopGetMain(), m_timer, kCFRunLoopDefaultMode);
+		CFRunLoopRemoveTimer(CFRunLoopGetCurrent(), m_timer, kCFRunLoopDefaultMode);
 
 		CFRelease(m_timer);
 		m_timer = nullptr;
@@ -142,9 +142,16 @@ int AudioToolboxMIDIDevice::Resume()
 			AUNode node;
 			AT_MIDI_CHECK_ERROR(AUGraphGetIndNode(graph, i, &node), false);
 
-			AudioComponentDescription desc = {};
 			AudioUnit audioUnit = nullptr;
+#if MAC_OS_X_VERSION_MAX_ALLOWED < 1050
+			ComponentDescription desc = {};
+			UInt32 classdatasize = 0;
+			void *classdata = nullptr;
+			AT_MIDI_CHECK_ERROR(AUGraphGetNodeInfo(graph, node, &desc, &classdatasize, &classdata, &audioUnit), false);
+#else // 10.5 and above
+			AudioComponentDescription desc = {};
 			AT_MIDI_CHECK_ERROR(AUGraphNodeInfo(graph, node, &desc, &audioUnit), false);
+#endif // prior to 10.5
 
 			if (   kAudioUnitType_Output           != desc.componentType
 				|| kAudioUnitSubType_DefaultOutput != desc.componentSubType)
@@ -260,7 +267,11 @@ bool AudioToolboxMIDIDevice::Preprocess(MIDIStreamer* song, bool looping)
 		return false;
 	}
 
+#if MAC_OS_X_VERSION_MAX_ALLOWED < 1050
+	AT_MIDI_CHECK_ERROR(MusicSequenceLoadSMFDataWithFlags(m_sequence, data, 0), false);
+#else // 10.5 and above
 	AT_MIDI_CHECK_ERROR(MusicSequenceFileLoadData(m_sequence, data, kMusicSequenceFile_MIDIType, 0), CFRelease(data), false);
+#endif // prior to 10.5
 
 	CFRelease(data);
 
diff --git a/src/stats.h b/src/stats.h
index f18159616..c82410db1 100644
--- a/src/stats.h
+++ b/src/stats.h
@@ -130,6 +130,15 @@ inline unsigned long long rdtsc()
 	unsigned long long tsc;
 	asm volatile ("rdtsc; shlq $32, %%rdx; orq %%rdx, %%rax" : "=a" (tsc) :: "%rdx");
 	return tsc;
+#elif defined __ppc__
+	unsigned int lower, upper, temp;
+	do
+	{
+		asm volatile ("mftbu %0 \n mftb %1 \n mftbu %2 \n" 
+			: "=r"(upper), "=r"(lower), "=r"(temp));
+	}
+	while (upper != temp);
+	return (static_cast<unsigned long long>(upper) << 32) | lower;
 #else // i386
 	if (CPU.bRDTSC)
 	{