Prevent crashes from extremely long lines

zig/sdl/hello_sdl.zig

                }
            }
            while (line != null and i * glyph_height < window_height) {
                const skipped_line = line.?[std.math.min(skip_horizontal, line.?.len)..];
                var skipped_line = line.?[std.math.min(skip_horizontal, line.?.len)..];
                if (skipped_line.len > line_buf.len) {
                    skipped_line = skipped_line[0 .. line_buf.len - 1];
                }
                // fix tabs
                const repl_size = std.mem.replacementSize(u8, skipped_line, "\t", " " ** 8);