make 'wait' optional and mark as workaround

Marlin/Configuration_adv.h

 #define MAX_CMD_SIZE 96
 #define BUFSIZE 4
 
+// Some Hosts doesn't have a timeout for resend a command.
+// This is a workaround for them. If your printer sometimes stuck and stop printing this could help.
+// #define NO_TIMEOUTS
+
 // @section fwretract
 
 // Firmware based and LCD controlled retract

Marlin/Marlin_main.cpp

 
   if (drain_queued_commands_P()) return; // priority is given to non-serial commands
   
-  static millis_t last_command_time = 0;
-  millis_t ms = millis();
+  #ifdef NO_TIMEOUTS
+    static millis_t last_command_time = 0;
+    millis_t ms = millis();
   
-  if (!MYSERIAL.available() && commands_in_queue == 0 && ms - last_command_time > 1000) {
-    SERIAL_ECHOLNPGM(MSG_WAIT);
-    last_command_time = ms;
-  }
+    if (!MYSERIAL.available() && commands_in_queue == 0 && ms - last_command_time > 1000) {
+      SERIAL_ECHOLNPGM(MSG_WAIT);
+      last_command_time = ms;
+    }
+  #endif
   
   while (MYSERIAL.available() > 0 && commands_in_queue < BUFSIZE) {
-    last_command_time = ms;
+    #ifdef NO_TIMEOUTS
+      last_command_time = ms;
+    #endif
     serial_char = MYSERIAL.read();
 
     if (serial_char == '\n' || serial_char == '\r' ||