2022: add PJW hash (lib)

2022/include/pjwhash.h

@@ -0,0 +1,20 @@
+/* pjwhash.h - PJW hash function, extern version.
+ *
+ * Copyright (C) 2021-2022 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 _PJWHASH_H
+#define _PJWHASH_H
+
+#include "bits.h"
+
+extern unsigned int  pjwhash(const char* str, uint length);
+
+#endif  /* _PJWHASH_H */