Define missing SNAPPY_PREFETCH macros.

PiperOrigin-RevId: 523287305

CMakeLists.txt

@@ -153,6 +153,12 @@ int main() {
   return __builtin_ctzll(0);
 }" HAVE_BUILTIN_CTZ)
 
+check_cxx_source_compiles("
+int main() {
+  __builtin_prefetch(0, 0, 3);
+  return 0;
+}" HAVE_BUILTIN_PREFETCH)
+
 check_cxx_source_compiles("
 __attribute__((always_inline)) int zero() { return 0; }