Qt4: On Mavericks the Xarch_x86_64 flag is not appropriate as the OS only supports 64 bit systems. However, Qt4 uses this flag in a way that is no longer compatiable on Mavericks. As a result, this causes Qt4 to fail to build. This commit comments out lines using those flags and simply adds the exact same line below with two patches that are applied. It may be worthwhile to actually create small pieces of code to test for Mavericks in particular so as not to break the build for other OSes.. However, this has not been done in this commit.