Reported by Jochen Sprickerhof, thanks!
Applied patch with minor change (only initialize `i` for XINERAMA).
static void
setup(void)
{
static void
setup(void)
{
unsigned int du;
XSetWindowAttributes swa;
XIM xim;
unsigned int du;
XSetWindowAttributes swa;
XIM xim;
lines = MAX(lines, 0);
mh = (lines + 1) * bh;
#ifdef XINERAMA
lines = MAX(lines, 0);
mh = (lines + 1) * bh;
#ifdef XINERAMA
if (parentwin == root && (info = XineramaQueryScreens(dpy, &n))) {
XGetInputFocus(dpy, &w, &di);
if (mon >= 0 && mon < n)
if (parentwin == root && (info = XineramaQueryScreens(dpy, &n))) {
XGetInputFocus(dpy, &w, &di);
if (mon >= 0 && mon < n)