Switching unpacket_traits<Packet4i> to vectorizable=true.

Eigen/src/Core/arch/AltiVec/PacketMath.h

diff --git a/Eigen/src/Core/arch/AltiVec/PacketMath.h b/Eigen/src/Core/arch/AltiVec/PacketMath.h
index 2bba3a7..154442c 100755
--- a/Eigen/src/Core/arch/AltiVec/PacketMath.h
+++ b/Eigen/src/Core/arch/AltiVec/PacketMath.h
@@ -190,7 +190,7 @@
 {
   typedef int       type;
   typedef Packet4i  half;
-  enum {size=4, alignment=Aligned16, vectorizable=false, masked_load_available=false, masked_store_available=false};
+  enum {size=4, alignment=Aligned16, vectorizable=true, masked_load_available=false, masked_store_available=false};
 };
 
 inline std::ostream & operator <<(std::ostream & s, const Packet16uc & v)