Update NEWS for 5.0.3.

NEWS

@@ -1,6 +1,38 @@
 
-XZ Utils User-Visible Changes
-=============================
+XZ Utils Release Notes
+======================
+
+5.0.3 (2011-05-21)
+
+    * liblzma fixes:
+
+        - A memory leak was fixed.
+
+        - lzma_stream_buffer_encode() no longer creates an empty .xz
+          Block if encoding an empty buffer. Such an empty Block with
+          LZMA2 data would trigger a bug in 5.0.1 and older (see the
+          first bullet point in 5.0.2 notes). When releasing 5.0.2,
+          I thought that no encoder creates this kind of files but
+          I was wrong.
+
+        - Validate function arguments better in a few functions. Most
+          importantly, specifying an unsupported integrity check to
+          lzma_stream_buffer_encode() no longer creates a corrupt .xz
+          file. Probably no application tries to do that, so this
+          shouldn't be a big problem in practice.
+
+        - Document that lzma_block_buffer_encode(),
+          lzma_easy_buffer_encode(), lzma_stream_encoder(), and
+          lzma_stream_buffer_encode() may return LZMA_UNSUPPORTED_CHECK.
+
+        - The return values of the _memusage() functions are now
+          documented better.
+
+    * Fix command name detection in xzgrep. xzegrep and xzfgrep now
+      correctly use egrep and fgrep instead of grep.
+
+    * French translation was added.
+
 
 5.0.2 (2011-04-01)