The last tool icon is not displayed when too many tools to display

[poppo]

If all tools cannot be displayed on the screen, you can switch the tools shown by clicking the arrow at the top of the tool list. However, the last tool icon is not displayed with that button.
I fix this bug: changing the value assigned to tool_selector_t::tool_icon_disp_start show_last_tool.patch

[prissi]

CHanged in r11878, using a simplier way for parsing.