Introduced the Build ID in INFO and --version output.

The idea is to be able to identify a build in a unique way, so for
instance after a bug report we can recognize that the build is the one
of a popular Linux distribution and perform the debugging in the same
environment.

src/rio.c

@@ -50,8 +50,7 @@
 #include <stdio.h>
 #include "rio.h"
 #include "util.h"
-
-uint64_t crc64(uint64_t crc, const unsigned char *s, uint64_t l);
+#include "crc64.h"
 
 /* Returns 1 or 0 for success/failure. */
 static size_t rioBufferWrite(rio *r, const void *buf, size_t len) {