[patch] ++/-- for AltiVec vectors

Hi all,

added support of ++/-- for AltiVec vectors according to "C/C++ Language Extensions for CBEA(Version 2.6)" section 10.3.
Attached is a fresh copy of the patch i've sent to cfe-commits a fiew days ago. Please review.

++_–_for_vectors.patch (2.91 KB)