* Add single output _mm_cvt[t]ss_* variants The *_pi variants are currently blocked by https://github.com/rust-lang-nursery/stdsimd/issues/74 * Add _mm_cvtsi*_ss The _mm_cvtpi*_ps intrinsics are blocked by https://github.com/rust-lang-nursery/stdsimd/issues/74 * Fix Linux builds Also the si64 variants are only available on x86_64