dwm: Add patch to fix monocle background transparency

Source: https://old.reddit.com/r/suckless/comments/jiyl4h/hiding_background_windows_in_monocle_and_deck/ga9fmc3/

assets/dwm-fix-monocle-transparency-background.patch

@@ -0,0 +1,31 @@
+diff --git a/dwm.c b/dwm.c
+index 67c6b2b..59666f7 100644
+--- a/dwm.c
++++ b/dwm.c
+@@ -808,6 +808,8 @@ focus(Client *c)
+ 		XDeleteProperty(dpy, root, netatom[NetActiveWindow]);
+ 	}
+ 	selmon->sel = c;
++  if (selmon->lt[selmon->sellt]->arrange == monocle)
++    arrangemon(selmon);
+ 	drawbars();
+ }
+ 
+@@ -1121,8 +1123,15 @@ monocle(Monitor *m)
+ 			n++;
+ 	if (n > 0) /* override layout symbol */
+ 		snprintf(m->ltsymbol, sizeof m->ltsymbol, "[%d]", n);
+-	for (c = nexttiled(m->clients); c; c = nexttiled(c->next))
+-		resize(c, m->wx, m->wy, m->ww - 2 * c->bw, m->wh - 2 * c->bw, 0);
++  for (c = m->stack; c && (!ISVISIBLE(c) || c->isfloating); c = c->snext);
++    if (c && !c->isfloating) {
++      XMoveWindow(dpy, c->win, m->wx, m->wy);
++      resize(c, m->wx, m->wy, m->ww - 2 * c->bw, m->wh - 2 * c->bw, 0);
++      c = c->snext;
++    }
++    for (; c; c = c->snext)
++      if (!c->isfloating && ISVISIBLE(c))
++        XMoveWindow(dpy, c->win, WIDTH(c) * -2, c->y);
+ }
+ 
+ void

specializations/dwm.nix

@@ -113,6 +113,8 @@ in
 
         package = pkgs.dwm.overrideAttrs (oldAttrs: {
           patches = oldAttrs.patches ++ [
+            ../assets/dwm-fix-monocle-transparency-background.patch
+
             (pkgs.fetchpatch {
               url = "https://dwm.suckless.org/patches/hide_vacant_tags/dwm-hide_vacant_tags-6.4.diff";
               hash = "sha256-GIbRW0Inwbp99rsKLfIDGvPwZ3pqihROMBp5vFlHx5Q=";