Update XZ Utils to 5.0.3 (in deps)

src/liblzma/api/lzma/index.h

Index: src/liblzma/api/lzma/index.h
===================================================================
--- src/liblzma/api/lzma/index.h	(revision 50504)
+++ src/liblzma/api/lzma/index.h	(working copy)
@@ -136,6 +136,13 @@
 		 *
 		 * This offset is relative to the beginning of the lzma_index
 		 * (i.e. usually the beginning of the .xz file).
+		 *
+		 * When doing random-access reading, it is possible that
+		 * the target offset is not exactly at Block boundary. One
+		 * will need to compare the target offset against
+		 * uncompressed_file_offset or uncompressed_stream_offset,
+		 * and possibly decode and throw away some amount of data
+		 * before reaching the target offset.
 		 */
 		lzma_vli uncompressed_file_offset;
 
@@ -166,14 +173,8 @@
 		 * \brief       Uncompressed size of this Block
 		 *
 		 * You should pass this to the Block decoder if you will
-		 * decode this Block.
-		 *
-		 * When doing random-access reading, it is possible that
-		 * the target offset is not exactly at Block boundary. One
-		 * will need to compare the target offset against
-		 * uncompressed_file_offset or uncompressed_stream_offset,
-		 * and possibly decode and throw away some amount of data
-		 * before reaching the target offset.
+		 * decode this Block. It will allow the Block decoder to
+		 * validate the uncompressed size.
 		 */
 		lzma_vli uncompressed_size;
 
@@ -181,7 +182,8 @@
 		 * \brief       Unpadded size of this Block
 		 *
 		 * You should pass this to the Block decoder if you will
-		 * decode this Block.
+		 * decode this Block. It will allow the Block decoder to
+		 * validate the unpadded size.
 		 */
 		lzma_vli unpadded_size;
 
@@ -583,7 +585,9 @@
  * \param       strm        Pointer to properly prepared lzma_stream
  * \param       i           Pointer to lzma_index which should be encoded.
  *
- * The only valid action value for lzma_code() is LZMA_RUN.
+ * The valid `action' values for lzma_code() are LZMA_RUN and LZMA_FINISH.
+ * It is enough to use only one of them (you can choose freely; use LZMA_RUN
+ * to support liblzma versions older than 5.0.0).
  *
  * \return      - LZMA_OK: Initialization succeeded, continue with lzma_code().
  *              - LZMA_MEM_ERROR
@@ -608,7 +612,9 @@
  * \param       memlimit    How much memory the resulting lzma_index is
  *                          allowed to require.
  *
- * The only valid action value for lzma_code() is LZMA_RUN.
+ * The valid `action' values for lzma_code() are LZMA_RUN and LZMA_FINISH.
+ * It is enough to use only one of them (you can choose freely; use LZMA_RUN
+ * to support liblzma versions older than 5.0.0).
  *
  * \return      - LZMA_OK: Initialization succeeded, continue with lzma_code().
  *              - LZMA_MEM_ERROR