sq_attackers() + others (see dedails). Ready for move do/undo ?

- add many "const" in func parameters
- attack.c: sq_attackers()
- move print_board_raw from position.c to to board.c
- move some fen_check() tests to pos_check()
- add REL_RANK() macro. TODO: add one more for bitboards
- fen.c: more tests for FEN validity
- position.c: add pos_checkers() and pos_check()
- tests: add common-test.h (for shared FEN positions access)

src/move-gen.h

@@ -0,0 +1,30 @@
+/* move-gen.h - move generation
+ *
+ * Copyright (C) 2024 Bruno Raoult ("br")
+ * Licensed under the GNU General Public License v3.0 or later.
+ * Some rights reserved. See COPYING.
+ *
+ * You should have received a copy of the GNU General Public License along with this
+ * program. If not, see <https://www.gnu.org/licenses/gpl-3.0-standalone.html>.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later <https://spdx.org/licenses/GPL-3.0-or-later.html>
+ *
+ */
+
+#ifndef MOVEGEN_H
+#define MOVEGEN_H
+
+#include "bitops.h"
+
+#include "bitboard.h"
+#include "hyperbola-quintessence.h"
+#include "piece.h"
+#include "move.h"
+
+/**
+ * gen_all_pseudomoves() - generate all pseudo moves
+ *
+ */
+int gen_all_pseudomoves(pos_t *pos);
+
+#endif  /* MOVEGEN_H */