diff --git a/INSTALL b/INSTALL
index a60347fc3..f994c4b17 100644
--- a/INSTALL
+++ b/INSTALL
@@ -33,6 +33,13 @@ Detailed build instructions are available at
 http://mumble.sourceforge.net/BuildingWindows and it is highly recommended
 to follow them to the letter.
 
+Mac OS X pre-requisites
+=======================
+
+Detailed build instructions are available at
+http://mumble.sourceforge.net/BuildingMacOSX and it is highly recommended
+to follow them to the letter.
+
 Linux pre-requisites
 ====================
 
@@ -63,10 +70,10 @@ So, to build without the server and without ASIO, the above line would be
 qmake main.pro CONFIG+=no-server CONFIG+=no-asio -recursive
 
 CONFIG+=no-client
- Don't build the client (mumble)
+ Don't build the client (Mumble)
 
 CONFIG+=no-server
- Don't build the server (murmur)
+ Don't build the server (Murmur)
 
 CONFIG+=no-bundled-speex
  Don't use the included version of Speex, but look for one on the system.
@@ -77,6 +84,10 @@ CONFIG+=optimize
  Build a heavily optimized version, specific to the machine it's being
  compiled on.
 
+CONFIG+=no-gcc42 (OSX)
+ Do not build with GCC 4.2 specific optimizations (MMX/SSE/SSE2 for
+ Universal Binaries), even though GCC 4.2 is availble on the system.
+
 CONFIG+=no-dbus (Mumble)
  Don't include DBus support on Mumble. This has no effect on Murmur, which
  requires DBus to work.
diff --git a/compiler.pri b/compiler.pri
index 8f7421c4f..1add08461 100644
--- a/compiler.pri
+++ b/compiler.pri
@@ -87,13 +87,7 @@ macx {
 			CONFIG += no-universal
 		}
 
-		CONFIG(no-universal) {
-			ARCH=$$system(uname -m)
-			contains(ARCH, 'i386') {
-				QMAKE_CFLAGS += -mmmx -msse
-				QMAKE_CXXFLAGS += -mmmx -msse
-			}
-		} else {
+		!CONFIG(no-universal) {
 			CONFIG += x86 ppc
 
 			# Precompiled headers are broken when using Makefiles.
@@ -101,7 +95,22 @@ macx {
 				CONFIG += no-pch
 			}
 		}
-	}	
+
+		ARCH=$$system(uname -m)
+		GCC42=$$system(readlink /usr/bin/gcc | grep "gcc-4.[2-9][.0-9]*")
+		!isEmpty(GCC42):!CONFIG(no-gcc42) {
+			QMAKE_MAC_SDK = /Developer/SDKs/MacOSX10.5.sdk
+			contains(ARCH, 'i386') {
+				QMAKE_CFLAGS += -Xarch_i386 -mmmx -Xarch_i386 -msse -Xarch_i386 -msse2
+				QMAKE_CXXFLAGS += -Xarch_i386 -mmmx -Xarch_i386 -msse -Xarch_i386 -msse2
+			}
+		} else {
+			CONFIG(no-universal):contains(ARCH, 'i386') {
+				QMAKE_CFLAGS += -mmmx -msse -msse2
+				QMAKE_CXXFLAGS += -mmmx -msse -msse2
+			}
+		}
+	}
 }
 
 CONFIG(no-pch) {
diff --git a/src/mumble/GlobalShortcut_macx.cpp b/src/mumble/GlobalShortcut_macx.cpp
index 45a4e8634..0a54e3d89 100644
--- a/src/mumble/GlobalShortcut_macx.cpp
+++ b/src/mumble/GlobalShortcut_macx.cpp
@@ -83,6 +83,7 @@ CGEventRef EventTapCallback(CGEventTapProxy proxy, CGEventType type,
 	unsigned int keycode;
 	bool suppress = false;
 	bool down = false;
+	int64_t repeat = 0;
 
 	switch (type) {
 		case kCGEventLeftMouseDown:
@@ -102,7 +103,7 @@ CGEventRef EventTapCallback(CGEventTapProxy proxy, CGEventType type,
 		case kCGEventKeyDown:
 			down = true;
 		case kCGEventKeyUp:
-			int64_t repeat = CGEventGetIntegerValueField(event, kCGKeyboardEventAutorepeat);
+			repeat = CGEventGetIntegerValueField(event, kCGKeyboardEventAutorepeat);
 			if (! repeat) {
 				keycode = static_cast<unsigned int>(CGEventGetIntegerValueField(event, kCGKeyboardEventKeycode));
 				suppress = gs->handleButton(keycode, down);