Use emptyString from LibreTiny v1.9.1

Author: kuba2k2

README.md

@@ -74,9 +74,11 @@ lib_deps =
 
 ### LibreTiny (BK7231N/T, RTL8710B, etc.)
 
+Version 1.9.1 or newer is required.
+
 ```ini
 [env:stable]
-platform = libretiny
+platform = libretiny @ ^1.9.1
 lib_ldf_mode = chain
 lib_deps =
   ESP32Async/AsyncTCP

platformio.ini

@@ -112,7 +112,7 @@ build_flags = ${env.build_flags}
   -Wno-missing-field-initializers
 
 [env:libretiny]
-platform = libretiny
+platform = libretiny @ ^1.9.1
 board = generic-bk7231n-qfn32-tuya
 ; board = generic-rtl8710bn-2mb-788k
 lib_deps =
@@ -168,7 +168,7 @@ build_flags = ${env.build_flags}
   -Wno-missing-field-initializers
 
 [env:ci-libretiny]
-platform = libretiny
+platform = libretiny @ ^1.9.1
 board = ${sysenv.PIO_BOARD}
 lib_deps =
   ESP32Async/AsyncTCP @ 3.4.3

src/ESPAsyncWebServer.h

@@ -1097,7 +1097,7 @@ class AsyncWebServer : public AsyncMiddlewareChain {
   void end();
 
   tcp_state state() const {
-#if defined(ESP8266) || defined(LIBRETINY)
+#ifdef ESP8266
     // ESPAsyncTCP and RPAsyncTCP methods are not corrected declared with const for immutable ones.
     return static_cast<tcp_state>(const_cast<AsyncWebServer *>(this)->_server.status());
 #else

src/literals.h

@@ -3,11 +3,6 @@
 
 #pragma once
 
-#ifdef LIBRETINY
-extern const String emptyStringForEspAsync;
-#define emptyString emptyStringForEspAsync
-#endif
-
 namespace asyncsrv {
 
 static constexpr const char *empty = "";