separate perft (from search.c)

src/perft.h

@@ -0,0 +1,22 @@
+/* perft.h.h - perft.
+ *
+ * Copyright (C) 2021-2024 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 PERFT_H
+#define PERFT_H
+
+#include "position.h"
+
+u64 perft(pos_t *pos, int depth, int ply, bool output);
+u64 perft_alt(pos_t *pos, int depth, int ply, bool output);
+
+#endif  /* PERFT_H */