check for !x86 platforms, otherwise the BTL benchmark doesn't compile on arm/powerpc
check for !x86 platforms, otherwise the BTL benchmark doesn't compile on arm/powerpc

rotorliu/eigen,mjbshaw/Eigen,mjbshaw/Eigen,madlib/eigen_backup,madlib/eigen_backup,madlib/eigen_backup,mjbshaw/Eigen,madlib/eigen_backup,rotorliu/eigen,rotorliu/eigen,rotorliu/eigen,mjbshaw/Eigen