The patch was originally written by dim@ and fixes the way Qt includes the
<mm3dnow.h> header. See the upstream commits' message for more information.
Practically speaking, this should make the Qt ports build with clang on i386
again, and allows us to revert commits r316233, r316348 and r316341: miwi
was very laconic in his commit messages, but the changes all point to the
issue being fixed here.
Submitted by: dim
760949cffa