[OpenCL patch] Vector literals are rvalues *updated*

The AltiVec PIM is not the only reference here. The "C/C++ Language Extensions for Cell Broadband Engine Architecture" <http://goo.gl/akXE0> updates the AltiVec PIM with additional syntax. Unfortunately, the GCC community took it upon themselves to dislike the original AltiVec PIM syntax and invented their own using curly braces which then became enshrined in this CBEA reference. See <http://gcc.gnu.org/ml/gcc/2001-11/msg01237.html>.