Apply ncurses patch to support clang compiler.

Using apple's command line tools, now that they are available independently of Xcode, seems to be the path forward for installing compilers on Mac. Therefore we need to be able to compile using clang. All of our current software works except for ncurses, which has accepted a patch to trunk but has not released since accepting the patch. I've added this patch and provided some references so we'll know it can be removed when the upstream fix is available.