Improve the speed of hashing in zippy compression.

This change replaces the hashing function used during compression with
one that is roughly as good but faster.  This speeds up compression by
two to a few percent on the Intel-, AMD-, and Arm-based machines we
tested.  The amount of compression is roughly unchanged.

PiperOrigin-RevId: 485960303

CMakeLists.txt

@@ -172,6 +172,19 @@ int main() {
   return 0;
 }" SNAPPY_HAVE_SSSE3)
 
+check_cxx_source_compiles("
+#include <immintrin.h>
+int main() {
+  return _mm_crc32_u32(0, 1);
+}" SNAPPY_HAVE_X86_CRC32)
+
+check_cxx_source_compiles("
+#include <arm_neon.h>
+#include <arm_acle.h>
+int main() {
+  return __crc32cw(0, 1);
+}" SNAPPY_HAVE_NEON_CRC32)
+
 check_cxx_source_compiles("
 #include <immintrin.h>
 int main() {