Update Pyrrhic; Advise to not look ahead mmap'ed TB files

Follows discussions that resulted from TCEC's use of 7-man TB. This is the only noticable differenc between Stockfish's implementation, and the implementation of many other engines. This patch was pointed out by Aloril, and I found the conversation that lead to it.

Rubi author claims to have found success in this patch, as have others. I am unable to verify that on my own local machines. However, there is no particular downside to this code.

NO FUNCTIONAL CHANGE

BENCH : 3,808,521

src/pyrrhic/tbchess.c

@@ -427,3 +427,4 @@ bool pyrrhic_legal_move(const PyrrhicPosition *pos, PyrrhicMove move) {
    PyrrhicPosition pos1;
    return pyrrhic_do_move(&pos1, pos, move);
 }
+

src/pyrrhic/tbprobe.c

@@ -203,6 +203,11 @@ static void *map_file(FD fd, map_t *mapping)
   *mapping = statbuf.st_size;
   void *data = mmap(NULL, statbuf.st_size, PROT_READ,
 			      MAP_SHARED, fd, 0);
+
+  #if defined(MADV_RANDOM)
+  madvise(data, statbuf.st_size, MADV_RANDOM);
+  #endif
+
   if (data == MAP_FAILED) {
     perror("mmap");
     return NULL;
@@ -2107,3 +2112,4 @@ static uint16_t probe_root(PyrrhicPosition *pos, int *score, unsigned *results)
         return 0;
     }
 }
+

src/uci.h

@@ -22,7 +22,7 @@
 
 #include "types.h"
 
-#define VERSION_ID "13.96"
+#define VERSION_ID "13.97"
 
 #ifndef LICENSE_OWNER
     #define LICENSE_OWNER "Unlicensed"