Suppresses 'Unknown Event' log messages from a2pid of David Schmenk's Apple II Pi https://github.com/dschmenk/apple2pi

a2pid.c.patch

--- src/a2pid.c	2021-08-16 01:50:14.596595180 -0700
+++ a2pid.c	2021-08-16 01:51:22.776233603 -0700
@@ -470,6 +470,7 @@
     fd_set readset, openset;
     char *devtty  = deftty;
     char *vdrvdir = "/usr/share/a2pi/"; /* default vdrv image directory */
+    char unk_msg[30]; /* for Unknown Event err msg test */
 
     /*
      * Parse arguments
@@ -896,8 +897,13 @@
 				//printf("vclock: resend request %04X\n", a2reqlist->type);
                             }
                             break;
+                        case 0x00: /* NULL event, received when Apple II is off */
+                              /* do nothing */
+                            break;
                         default:
-                            prlog("a2pid: Unknown Event\n");
+                            // prlog("a2pid: Unknown Event\n");
+                            sprintf(unk_msg, "a2pid: Unknown Event: %0x\n", iopkt[0]);
+                            prlog(unk_msg);
                             tcflush(a2fd, TCIFLUSH);
                             //stop = TRUE;
                     }