(svn r15287) -Cleanup: some code style, remove erroneous comment.

-Document: the fact that zlib reads uninitialised data (valgrind notices this) and that it won't be fixed in zlib and that we can't do anything about it except ignoring it.

src/saveload/saveload.cpp

@@ -1255,7 +1255,7 @@ static bool InitWriteZlib()
 	if (deflateInit(&_z, 6) != Z_OK) return false;
 
 	_sl.bufsize = 4096;
-	_sl.buf = _sl.buf_ori = MallocT<byte>(4096); // also contains fread buffer
+	_sl.buf = _sl.buf_ori = MallocT<byte>(4096);
 	return true;
 }
 
@@ -1269,7 +1269,16 @@ static void WriteZlibLoop(z_streamp z, byte *p, size_t len, int mode)
 	do {
 		z->next_out = buf;
 		z->avail_out = sizeof(buf);
+
+		/**
+		 * For the poor next soul who sees many valgrind warnings of the
+		 * "Conditional jump or move depends on uninitialised value(s)" kind:
+		 * According to the author of zlib it is not a bug and it won't be fixed.
+		 * http://groups.google.com/group/comp.compression/browse_thread/thread/b154b8def8c2a3ef/cdf9b8729ce17ee2
+		 * [Mark Adler, Feb 24 2004, 'zlib-1.2.1 valgrind warnings' in the newgroup comp.compression]
+		 **/
 		r = deflate(z, mode);
+
 		/* bytes were emitted? */
 		if ((n = sizeof(buf) - z->avail_out) != 0) {
 			if (fwrite(buf, n, 1, _sl.fh) != 1) SlError(STR_GAME_SAVELOAD_ERROR_FILE_NOT_WRITEABLE);