has_trivial_copy_assign hooked up to clang (without workarounds). Filed...

has_trivial_copy_assign hooked up to clang (without workarounds).  Filed http://llvm.org/bugs/show_bug.cgi?id=8109 to take care of several types which don't work yet.  If there is some reason we don't want to handle these types in the compiler, I can handle most of them in the library.

llvm-svn: 113312