Build failure in C23 mode

[ryandesign]

Building sysbench fails when the compiler is in C23 mode.

autoconf 2.73 puts the compiler into C23 mode by default if the compiler supports it.

crc32.c:194:29: error: unknown type name 'crc'
  194 | unsigned long ZEXPORT crc32(crc, buf, len)
      |                             ^
crc32.c:194:34: error: unknown type name 'buf'
  194 | unsigned long ZEXPORT crc32(crc, buf, len)
      |                                  ^
crc32.c:194:39: error: unknown type name 'len'
  194 | unsigned long ZEXPORT crc32(crc, buf, len)
      |                                       ^
crc32.c:194:43: error: expected ';' after top level declarator
  194 | unsigned long ZEXPORT crc32(crc, buf, len)
      |                                           ^
      |                                           ;
crc32.c:198:1: error: expected identifier or '('
  198 | {
      | ^

Old-style K&R function definitions are no longer supported:

sysbench/src/tests/fileio/crc32.c

Lines 194 to 198 in 3ceba0b

	unsigned long ZEXPORT crc32(crc, buf, len)
	unsigned long crc;
	const unsigned char FAR *buf;
	unsigned len;
	{

The upstream version of crc32.c has fixed these problems already:

https://github.com/madler/zlib/commits/develop/crc32.c