Fix build on ncurses-6.3

From: https://github.com/baszoetekouw/pinfo/pull/27
====
diff --git a/src/utils.c b/src/utils.c
index 2e4139c..34c9b88 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -394,7 +394,7 @@ getstring_with_completion(char *prompt, const char * const * completions)
 	curs_set(0);
 
 #else
-
+	(void)completions; /* unused */
 	move(maxy - 1, 0);
 	buf = readlinewrapper(prompt);
 
diff --git a/src/video.c b/src/video.c
index f6b444a..195d781 100644
--- a/src/video.c
+++ b/src/video.c
@@ -109,9 +109,9 @@ showscreen(char **message, unsigned long lines, unsigned long pos, long cursor,
 	mymvhline(maxy - 1, 0, ' ', maxx);
 	move(maxy - 1, 0);
 	if ((pos < lines - 1) &&(lines > pos + maxy - 2))
-		printw(_("Viewing line %d/%d, %d%%"), pos + maxy - 2, lines,((pos + maxy - 2) * 100) / lines);
+		printw(_("Viewing line %ld/%ld, %ld%%"), pos + maxy - 2, lines,((pos + maxy - 2) * 100) / lines);
 	else
-		printw(_("Viewing line %d/%d, 100%%"), lines, lines);
+		printw(_("Viewing line %ld/%ld, 100%%"), lines, lines);
 	info_add_highlights(pos, cursor, lines, column, message);
 	attrset(normal);
 	move(0, 0);