legion: fixes for altivec header file to comply with c++ standards
legion: fixes for altivec header file to comply with c++ standards

StanfordLegion/legion,StanfordLegion/legion,StanfordLegion/legion,StanfordLegion/legion,StanfordLegion/legion,StanfordLegion/legion,StanfordLegion/legion,StanfordLegion/legion