silence Rust 1.38.0 warning

Author: hkratz

src/implementation/algorithm.rs

@@ -193,6 +193,7 @@ macro_rules! algorithm_simd {
             #[target_feature(enable = $feat)]
             #[inline]
             #[allow(unconditional_panic)] // does not panic because len is checked
+            #[allow(const_err)] // the same, but for Rust 1.38.0
             unsafe fn check_block(&mut self, input: SimdInput) {
                 // necessary because a for loop is not unrolled on ARM64
                 if input.vals.len() == 2 {