xor_combine_engine needed these changes to mpl/math.h.
xor_combine_engine needed these changes to mpl/math.h.

--HG--
extra : convert_revision : svn%3A83215879-3e5a-4751-8c9d-778f44bb06a5/trunk%40701

mohamed-ali/thrust,arnabgho/thrust,xiongzhanblake/thrust,raygit/thrust,mohamed-ali/thrust,andrewcorrigan/thrust-multi-permutation-iterator,xiongzhanblake/thrust,GrimDerp/thrust,jaredhoberock/thrust,dachziegel/thrust,sarvex/thrust,andrewcorrigan/thrust-multi-permutation-iterator,xiongzhanblake/thrust,thrust/thrust,thvasilo/thrust,marksantos/thrust,zeryx/thrust,sdalton1/thrust,GrimDerp/thrust,zhenglaizhang/thrust,zhenglaizhang/thrust,raygit/thrust,zhenglaizhang/thrust,GrimDerp/thrust,egaburov/thrust,arnabgho/thrust,andrewcorrigan/thrust-multi-permutation-iterator,Ricardo666666/thrust,thrust/thrust,egaburov/thrust,jaredhoberock/thrust,jaredhoberock/thrust,zeryx/thrust,marksantos/thrust,Ricardo666666/thrust,xiongzhanblake/thrust_src,xiongzhanblake/thrust_src,jaredhoberock/thrust,jaredhoberock/thrust,marksantos/thrust,zeryx/thrust,sdalton1/thrust,thrust/thrust,thrust/thrust,raygit/thrust,thrust/thrust,Ricardo666666/thrust,thvasilo/thrust,arnabgho/thrust,thvasilo/thrust,sarvex/thrust,xiongzhanblake/thrust_src,dachziegel/thrust,egaburov/thrust,mohamed-ali/thrust,dachziegel/thrust,sdalton1/thrust,sarvex/thrust