Add Common::AtomicDecrement for gcc to match win32.

Use the debug option for conf.CheckWXConfig on OS X as on Unix.

Take care of a few compiler warnings.


git-svn-id: https://dolphin-emu.googlecode.com/svn/trunk@6084 8ced0084-cf51-0410-be5f-012b33b47a6e

Source/Core/Common/Src/Atomic_GCC.h

@@ -45,6 +45,10 @@ inline void AtomicAnd(volatile u32& target, u32 value) {
 	__sync_and_and_fetch(&target, value);
 }
 
+inline void AtomicDecrement(volatile u32& target) {
+	__sync_add_and_fetch(&target, -1);
+}
+
 inline void AtomicIncrement(volatile u32& target) {
 	__sync_add_and_fetch(&target, 1);
 }