Update XZ Utils to 5.0.3 (in deps)

src/liblzma/common/stream_buffer_encoder.c

Index: src/liblzma/common/stream_buffer_encoder.c
===================================================================
--- src/liblzma/common/stream_buffer_encoder.c	(revision 50504)
+++ src/liblzma/common/stream_buffer_encoder.c	(working copy)
@@ -51,6 +51,9 @@
 			|| out_pos_ptr == NULL || *out_pos_ptr > out_size)
 		return LZMA_PROG_ERROR;
 
+	if (!lzma_check_is_supported(check))
+		return LZMA_UNSUPPORTED_CHECK;
+
 	// Note for the paranoids: Index encoder prevents the Stream from
 	// getting too big and still being accepted with LZMA_OK, and Block
 	// encoder catches if the input is too big. So we don't need to
@@ -81,27 +84,33 @@
 
 	out_pos += LZMA_STREAM_HEADER_SIZE;
 
-	// Block
+	// Encode a Block but only if there is at least one byte of input.
 	lzma_block block = {
 		.version = 0,
 		.check = check,
 		.filters = filters,
 	};
 
-	return_if_error(lzma_block_buffer_encode(&block, allocator,
-			in, in_size, out, &out_pos, out_size));
+	if (in_size > 0)
+		return_if_error(lzma_block_buffer_encode(&block, allocator,
+				in, in_size, out, &out_pos, out_size));
 
 	// Index
 	{
-		// Create an Index with one Record.
+		// Create an Index. It will have one Record if there was
+		// at least one byte of input to encode. Otherwise the
+		// Index will be empty.
 		lzma_index *i = lzma_index_init(allocator);
 		if (i == NULL)
 			return LZMA_MEM_ERROR;
 
-		lzma_ret ret = lzma_index_append(i, allocator,
-				lzma_block_unpadded_size(&block),
-				block.uncompressed_size);
+		lzma_ret ret = LZMA_OK;
 
+		if (in_size > 0)
+			ret = lzma_index_append(i, allocator,
+					lzma_block_unpadded_size(&block),
+					block.uncompressed_size);
+
 		// If adding the Record was successful, encode the Index
 		// and get its size which will be stored into Stream Footer.
 		if (ret == LZMA_OK) {