Fix vertical lines in Putty with UTF-8 graphics

Putty doesn't show VT100 line drawing characters in the UTF-8 mode by
default. Putty 0.70 and older doesn't even have that option.

For the vertical display separator, output the vertical line character on
every line.

For the line number separator, use code similar to the graph drawing
code. Use draw_graphic() in the DEFAULT mode only, draw_chars()
otherwise.

Closes #981

src/display.c

@@ -187,11 +187,18 @@ static void
 redraw_display_separator(bool clear)
 {
 	if (display_sep) {
-		chtype separator = opt_line_graphics ? ACS_VLINE : '|';
+		chtype separator = (opt_line_graphics == GRAPHIC_DEFAULT) ? ACS_VLINE : '|';
 
 		if (clear)
 			wclear(display_sep);
 		wbkgd(display_sep, separator + get_line_attr(NULL, LINE_TITLE_BLUR));
+
+		if (opt_line_graphics == GRAPHIC_UTF_8) {
+			int lineno = 0;
+
+			while (mvwaddstr(display_sep, lineno++, 0, "│") == OK);
+		}
+
 		wnoutrefresh(display_sep);
 	}
 }

src/draw.c

@@ -314,7 +314,7 @@ draw_lineno_custom(struct view *view, struct view_column *column, unsigned int l
 	unsigned long digits3 = MIN(9,MAX(3,column->width));
 	int max = MIN(VIEW_MAX_LEN(view), digits3);
 	char *text = NULL;
-	chtype separator = opt_line_graphics ? ACS_VLINE : '|';
+	chtype separator = ACS_VLINE;
 	struct line_number_options *opts = &column->opt.line_number;
 	int interval = opts->interval > 0 ? opts->interval : 5;
 
@@ -332,7 +332,17 @@ draw_lineno_custom(struct view *view, struct view_column *column, unsigned int l
 		draw_chars(view, LINE_LINE_NUMBER, text, -1, max, true);
 	else
 		draw_space(view, LINE_LINE_NUMBER, max, digits3);
-	return draw_graphic(view, LINE_DEFAULT, &separator, 1, true);
+
+	switch (opt_line_graphics) {
+	case GRAPHIC_ASCII:
+		return draw_chars(view, LINE_DEFAULT, "| ", -1, 2, false);
+	case GRAPHIC_DEFAULT:
+		return draw_graphic(view, LINE_DEFAULT, &separator, 1, true);
+	case GRAPHIC_UTF_8:
+		return draw_chars(view, LINE_DEFAULT, "│ ", -1, 2, false);
+	}
+
+	return false;
 }
 
 bool