Merge pull request #11966 from aclamk/wip-linear-zeros-crc

common: Improved CRC calculation for zero buffers

diff --cc src/include/crc32c.h
index 35b6cafcc3a58326109a380ae93c004152ee3642,f2a3b39d43f5a783286c60811bbe3a3780524895..86d9c8d229caaeac57808b567b4bbae2d94bf394
--- 1/src/include/crc32c.h
--- 2/src/include/crc32c.h
+++ b/src/include/crc32c.h
@@@ -1,8 -1,13 +1,12 @@@
  #ifndef CEPH_CRC32C_H
  #define CEPH_CRC32C_H
  
 -#include <inttypes.h>
 -#include <string.h>
 +#include <stdint.h>
  
+ #ifdef __cplusplus
+ extern "C" {
+ #endif
+ 
  typedef uint32_t (*ceph_crc32c_func_t)(uint32_t crc, unsigned char const *data, unsigned length);
  
  /*