Various changes suggested by cppcheck

- remove unused variables
- reduce the scope where it makes sense
- correct limits (did you know that strcat()'s last parameter does not
  include the \0 that is always added?)
- set some free()'d pointers to NULL

Source/Core/Common/ArmEmitter.h

@@ -735,8 +735,8 @@ public:
 	{
 #ifndef __SYMBIAN32__
 		FreeMemoryPages(region, region_size);
-#endif
 		region = NULL;
+#endif
 		region_size = 0;
 	}