fix: all: fixes to get emacs-chess working on 30.2

- added lexical-binding headers to all source files
- replaced make-variable-buffer-local with defvar-local throughout source code
- replaced deprecated cl library with cl-lib, including replacing assert with cl-assert to emacs-chess-steps.el
- added proper headers and footers to test files when missing
- populated chess images and chess sounds directory
- fixed defcustom calling directory-files without error handling.
  xboard installation no longer required.

2 files changed, 42 insertions, 0 deletions

diff --git a/pieces b/pieces
deleted file mode 160000
-Subproject e1fd1a04010df93f18ff1c1d8d62ea23ce96029
diff --git a/pieces/xboard/ndl33.xpm b/pieces/xboard/ndl33.xpm
new file mode 100644
index 0000000..6e35445
--- /dev/null
+++ b/pieces/xboard/ndl33.xpm
@@ -0,0 +1,42 @@
+/* XPM */
+static char *ndl33[] = {
+/* columns rows colors chars-per-pixel */
+"33 33 3 1",
+"  c black s dark_piece",
+". c gray s light_square",
+"X c white s light_piece",
+/* pixels */
+".................................",
+".................................",
+".................................",
+"............... .................",
+".........  ...  .................",
+".........   ..   ................",
+".........          ..............",
+".........   XX   XX  ............",
+".........  X       XX  ..........",
+"........             X  .........",
+"........  XX          X  ........",
+".......  X             X  .......",
+".......  X             XX .......",
+"......                  X  ......",
+"......                  XX ......",
+".....            X       X  .....",
+".....                    XX .....",
+"....                     XX .....",
+"....           ..         X  ....",
+"...  X       ....         XX ....",
+"...  X      ....          XX ....",
+"...        .....          XX ....",
+"...       .....            X ....",
+"....     .....             X  ...",
+".............              XX ...",
+"............               XX ...",
+"...........                XX ...",
+"...........                XX ...",
+"..........                 XX ...",
+"..........                    ...",
+"..........                    ...",
+".................................",
+"................................."
+};