Use correct colormap with -t

Using the default colormap on a drawable w/ specific (ARGB) colormap for
rendering the arcs will lead to random colors being picked (typically
"white", but it can actually be anything) for the arcs. You have to use
the colormap specific to the drawawble (window)

Patch by luebking

Fixes #26

find-cursor.c

@@ -259,10 +259,12 @@ void draw(char *name, Display *display, int screen,
 	XSetWindowAttributes window_attr;
 	window_attr.override_redirect = 1;
 
+	Colormap colormap = DefaultColormap(display, screen);
 	if (transparent) {
 		XVisualInfo vinfo;
 		XMatchVisualInfo(display, screen, 32, TrueColor, &vinfo);
 		window_attr.colormap = XCreateColormap(display, DefaultRootWindow(display), vinfo.visual, AllocNone);
+		colormap = window_attr.colormap;
 		window_attr.background_pixel = 0;
 		window = XCreateWindow(display, XRootWindow(display, screen),
 			center_x,                               // x position
@@ -349,7 +351,6 @@ void draw(char *name, Display *display, int screen,
 	GC gc = XCreateGC(display, window, valuemask, &values);
 
 	// Get colours.
-	Colormap colormap = DefaultColormap(display, screen);
 	XColor color;
 	int err = XAllocNamedColor(display, colormap, color_name, &color, &color);
 	if (err == 0) {