Add my upstream patch to make these Qt ports build with libc++.
The original patch was written by Jan Beich in the PR mentioned
below. I haven't been able to fully build x11/qt4-opengl yet due to
other errors which show up later, but at least this one problem is
solved, and the fix will be included in the next Qt 4.8 release.
No PORTREVISION bump, as users of other standard C++ libraries are not
affected, and no dependencies have been changed.
Submitted by: Jan Beich <email@example.com>