This patch allows to build jack-rack with ALSA support disabled.
See bug #135966.

Index: jack-rack-1.4.6/src/plugin_slot_callbacks.c
===================================================================
--- jack-rack-1.4.6.orig/src/plugin_slot_callbacks.c
+++ jack-rack-1.4.6/src/plugin_slot_callbacks.c
@@ -99,6 +99,7 @@ slot_ablise_cb (GtkWidget * button, GdkE
 	    
 	      return TRUE;
 	    }
+#ifdef HAVE_ALSA
 	  case 3:
 	    {
 	      ui_t * ui;
@@ -119,6 +120,7 @@ slot_ablise_cb (GtkWidget * button, GdkE
 	    
 	      return TRUE;
 	    }
+#endif
       }
     }