Use FreeBSD's MD5-implementation instead of yet another bundled one.

	-mi

--- common/CMakeLists.txt	2016-01-25 00:16:50.000000000 -0500
+++ common/CMakeLists.txt	2016-02-02 17:57:52.620700000 -0500
@@ -109,5 +109,4 @@
     threadpool.cpp threadpool.h
     wavefront.h wavefront.cpp
-    md5.cpp md5.h
     bitstream.h bitstream.cpp
     yuv.cpp yuv.h
--- common/picyuv.h	2016-01-25 00:16:50.000000000 -0500
+++ common/picyuv.h	2016-02-02 21:52:24.690114000 -0500
@@ -25,6 +25,8 @@
 #define X265_PICYUV_H
 
+#include <sys/types.h>
+#include <md5.h>
+
 #include "common.h"
-#include "md5.h"
 #include "x265.h"
 
--- encoder/frameencoder.cpp	2016-01-25 00:16:50.000000000 -0500
+++ encoder/frameencoder.cpp	2016-02-02 18:06:58.918647000 -0500
@@ -667,5 +667,5 @@
             m_seiReconPictureDigest.m_method = SEIDecodedPictureHash::MD5;
             for (int i = 0; i < planes; i++)
-                MD5Final(&m_state[i], m_seiReconPictureDigest.m_digest[i]);
+                MD5Final(m_seiReconPictureDigest.m_digest[i], &m_state[i]);
         }
         else if (m_param->decodedPictureHashSEI == 2)