bug#16306: 24.3.50; font change creates blank column on Lucid

[martin rudalics]

> The native scroll bar is the same width as a character.  Not sure if the 
pixelwise resize changed that.

Can you tell me how this is processed in this part of x_new_font of
Emacs 24.3?  I'm too silly to understand its semantics.


  /* Compute the scroll bar width in character columns.  */
  if (FRAME_CONFIG_SCROLL_BAR_WIDTH (f) > 0)
    {
      int wid = FRAME_COLUMN_WIDTH (f);
      FRAME_CONFIG_SCROLL_BAR_COLS (f)
        = (FRAME_CONFIG_SCROLL_BAR_WIDTH (f) + wid-1) / wid;
    }
  else
    {
      int wid = FRAME_COLUMN_WIDTH (f);
      FRAME_CONFIG_SCROLL_BAR_COLS (f) = (14 + wid - 1) / wid;
    }

martin