The test to detect if the CPU was SSE2-enabled using __get_cpuid was reversed; configure.ac was testing for the presence of emmintrin.h before detecting which compiler option turned on SSE2, and the header cannot be used until that switch has been set

git-svn-id: https://svn.apache.org/repos/asf/xerces/c/trunk@808881 13f79535-47bb-0310-9956-ffa450edef68