Merge branch '2.3' into 2.4

radio/src/lua/api_general.cpp

@@ -1537,6 +1537,19 @@ static int luaGetUsage(lua_State * L)
   return 1;
 }
 
+/*luadoc
+@function getAvailableMemory()
+
+Get available memory remaining in the Heap for Lua.
+
+@retval usage (number) a value returned in b
+*/
+static int luaGetAvailableMemory(lua_State * L)
+{
+  lua_pushunsigned(L, availableMemory());
+  return 1;
+}
+
 /*luadoc
 @function resetGlobalTimer([type])
 
@@ -1764,6 +1777,7 @@ const luaL_Reg opentxLib[] = {
   { "chdir", luaChdir },
   { "loadScript", luaLoadScript },
   { "getUsage", luaGetUsage },
+  { "getAvailableMemory", luaGetAvailableMemory },
   { "resetGlobalTimer", luaResetGlobalTimer },
 #if LCD_DEPTH > 1 && !defined(COLORLCD)
   { "GREY", luaGrey },