Adding upstream version 2.13.1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

lib/compression.h

@@ -0,0 +1,42 @@
+/*
+ * compression.h: interface to finding decompressor / compression extension
+ *
+ * Copyright (C) 1994, 1995 Graeme W. Wilford. (Wilf.)
+ * Copyright (C) 2001-2022 Colin Watson.
+ *
+ * This file is part of man-db.
+ *
+ * man-db is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * man-db is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with man-db; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <stdbool.h>
+
+struct compression {
+	/* The following are const because they should be pointers to parts
+	 * of strings allocated elsewhere and should not be written through
+	 * or freed themselves.
+	 */
+	const char *prog;
+	const char *ext;
+	/* The following should be freed when discarding an instance of this
+	 * structure.
+	 */
+	char *stem;
+};
+
+extern struct compression comp_list[];
+
+extern struct compression *comp_info (const char *filename, bool want_stem);
+extern struct compression *comp_file (const char *filename);