When a selection containing no more than 256 distinct colors is copied
from a 24-bit image, xv uses 8-bit color on the clipboard, presumably
in order to optimize clipboard size if the selection is large.
This patch fixes a bug that was causing the colormap it constructs
to be stored one place off the correct position in the data structure.

Signed-off-by: Mark Brader <msb@vex.net>
Acked-by: Gabriel Somlo <somlo@cmu.edu>

diff -NarU5 a/xvcut.c b/xvcut.c
--- a/xvcut.c	2013-03-28 12:36:30.515468841 -0400
+++ b/xvcut.c	2013-03-28 12:37:34.639145150 -0400
@@ -676,13 +676,13 @@
 	for (k=0; k<nc; k++,cm+=3) {
 	  if (pr==cm[0] && pg==cm[1] && pb==cm[2]) break;
 	}
 	if (k==nc) {
 	  nc++;
-	  cimg[CIMG_CMAP + nc*3    ] = pr;
-	  cimg[CIMG_CMAP + nc*3 + 1] = pg;
-	  cimg[CIMG_CMAP + nc*3 + 2] = pb;
+	  cimg[CIMG_CMAP + k*3    ] = pr;
+	  cimg[CIMG_CMAP + k*3 + 1] = pg;
+	  cimg[CIMG_CMAP + k*3 + 2] = pb;
 	}
 
 	*dp++ = (byte) k;
       }
     }