Update FLAC to 1.3.1

src/libFLAC/include/private/md5.h

 #ifndef FLAC__PRIVATE__MD5_H
 #define FLAC__PRIVATE__MD5_H
 
 /*
  * This is the header file for the MD5 message-digest algorithm.
  * The algorithm is due to Ron Rivest.  This code was
  * written by Colin Plumb in 1993, no copyright is claimed.
  * This code is in the public domain; do with it what you wish.
  *
  * Equivalent code is available from RSA Data Security, Inc.
@@ skipping 10 matching lines @@
  * header definitions; now uses stuff from dpkg's config.h
  *  - Ian Jackson <ijackson@nyx.cs.du.edu>.
  * Still in the public domain.
  *
  * Josh Coalson: made some changes to integrate with libFLAC.
  * Still in the public domain, with no warranty.
  */
 
 #include "FLAC/ordinals.h"
 
+typedef union {
+        FLAC__byte *p8;
+        FLAC__int16 *p16;
+        FLAC__int32 *p32;
+} FLAC__multibyte;
+
 typedef struct {
         FLAC__uint32 in[16];
         FLAC__uint32 buf[4];
         FLAC__uint32 bytes[2];
-        FLAC__byte *internal_buf;
+        FLAC__multibyte internal_buf;
         size_t capacity;
 } FLAC__MD5Context;
 
 void FLAC__MD5Init(FLAC__MD5Context *context);
 void FLAC__MD5Final(FLAC__byte digest[16], FLAC__MD5Context *context);
 
 FLAC__bool FLAC__MD5Accumulate(FLAC__MD5Context *ctx, const FLAC__int32 * const signal[], unsigned channels, unsigned samples, unsigned bytes_per_sample);
 
 #endif