fix #H4237 - color ignored for X11 text map

fix #H4237 - color ignored for X11 text map

Color was only being tracked for locations that had the pile of
objects flag set.  And hilite_pile made a monster on a pile take
on the color of the top object of the pile.

This restores the tracking of color for the whole map, and makes
highlighted piles be drawn in inverse like highligted pets.  The
drawing routine doesn't know the difference (but could tell, if
necessary, by testing whether the glyph is an object or a monster).

Also, variables 'inbuf', 'inptr', and 'incount' were global; limit
their scope to winmap.c.