Fix Host Keepalive serial target (#21283)

Co-authored-by: Scott Lahteine <github@thinkyhead.com>

Marlin/src/HAL/ESP32/FlushableHardwareSerial.h

  */
 #pragma once
 
-#ifdef ARDUINO_ARCH_ESP32
-
 #include <HardwareSerial.h>
+
+#include "../shared/Marduino.h"
 #include "../../core/serial_hook.h"
 
 class FlushableHardwareSerial : public HardwareSerial {
 };
 
 extern Serial0Type<FlushableHardwareSerial> flushableSerial;
-
-#endif // ARDUINO_ARCH_ESP32

Marlin/src/core/serial.h

 //
 // Serial redirection
 //
-#define SERIAL_ALL 0x7F
+#define SERIAL_ALL 0xFF
 #if HAS_MULTI_SERIAL
   #define _PORT_REDIRECT(n,p)   REMEMBER(n,multiSerial.portMask,p)
   #define _PORT_RESTORE(n,p)    RESTORE(n)

Marlin/src/core/serial_hook.h

   RuntimeSerial(const bool e, Args... args) : BaseClassT(e), SerialT(args...), writeHook(0), eofHook(0), userPointer(0) {}
 };
 
-// A class that's duplicating its output conditionally to 2 serial interface
+// A class that duplicates its output conditionally to 2 serial interfaces
 template <class Serial0T, class Serial1T, const uint8_t offset = 0, const uint8_t step = 1>
 struct MultiSerial : public SerialBase< MultiSerial<Serial0T, Serial1T, offset, step> > {
   typedef SerialBase< MultiSerial<Serial0T, Serial1T, offset, step> > BaseClassT;

Marlin/src/gcode/gcode.cpp

     static millis_t next_busy_signal_ms = 0;
     if (!autoreport_paused && host_keepalive_interval && busy_state != NOT_BUSY) {
       if (PENDING(ms, next_busy_signal_ms)) return;
+      PORT_REDIRECT(SERIAL_ALL);
       switch (busy_state) {
         case IN_HANDLER:
         case IN_PROCESS:

Marlin/src/gcode/queue.cpp

   SERIAL_ECHOLN(serial_state[serial_ind].last_N + 1);
 }
 
-// Multiserial already handle the dispatch to/from multiple port by itself
-inline bool serial_data_available(uint8_t index = SERIAL_ALL) {
-  if (index == SERIAL_ALL) {
-    for (index = 0; index < NUM_SERIAL; index++) {
-      const int a = SERIAL_IMPL.available(index);
-      #if BOTH(RX_BUFFER_MONITOR, RX_BUFFER_SIZE)
-        if (a > RX_BUFFER_SIZE - 2) {
-          PORT_REDIRECT(SERIAL_PORTMASK(index));
-          SERIAL_ERROR_MSG("RX BUF overflow, increase RX_BUFFER_SIZE: ", a);
-        }
-      #endif
-      if (a > 0) return true;
-    }
-    return false;
-  }
+inline bool serial_data_available(uint8_t index) {
   const int a = SERIAL_IMPL.available(index);
   #if BOTH(RX_BUFFER_MONITOR, RX_BUFFER_SIZE)
     if (a > RX_BUFFER_SIZE - 2) {
       SERIAL_ERROR_MSG("RX BUF overflow, increase RX_BUFFER_SIZE: ", a);
     }
   #endif
-
   return a > 0;
 }
 
+// Multiserial already handles dispatch to/from multiple ports
+inline bool any_serial_data_available() {
+  LOOP_L_N(p, NUM_SERIAL)
+    if (serial_data_available(p))
+      return true;
+}
+
 inline int read_serial(const uint8_t index) { return SERIAL_IMPL.read(index); }
 
 void GCodeQueue::gcode_line_error(PGM_P const err, const serial_index_t serial_ind) {
   // send "wait" to indicate Marlin is still waiting.
   #if NO_TIMEOUTS > 0
     const millis_t ms = millis();
-    if (ring_buffer.empty() && !serial_data_available() && ELAPSED(ms, last_command_time + NO_TIMEOUTS)) {
+    if (ring_buffer.empty() && !any_serial_data_available() && ELAPSED(ms, last_command_time + NO_TIMEOUTS)) {
       SERIAL_ECHOLNPGM(STR_WAIT);
       last_command_time = ms;
     }

platformio.ini

 MORGAN_SCARA            = src_filter=+<src/gcode/scara>
 HAS_MICROSTEPS          = src_filter=+<src/gcode/control/M350_M351.cpp>
 (ESP3D_)?WIFISUPPORT    = AsyncTCP, ESP Async WebServer
-  ESP3DLib=https://github.com/luc-github/ESP3DLib.git
-  arduinoWebSockets=https://github.com/Links2004/arduinoWebSockets.git
-  ESP32SSDP=https://github.com/luc-github/ESP32SSDP.git
+  ESP3DLib=https://github.com/luc-github/ESP3DLib/archive/master.zip
+  arduinoWebSockets=links2004/WebSockets@2.3.4
+  luc-github/ESP32SSDP@^1.1.1
   lib_ignore=ESPAsyncTCP
 
 #