String Function Do not work at AURIX SB TC 375

Hello Admin .
I am having trouble compiling a sketch code in Arduino IDE 1.8.19 with Hardware Aurix Shieldbuddy TC 375
Using Infineon User Manual , we are install it.
- The standard Arduino IDE installed from:
www.arduino.cc/en/Main/Software
- free-entry-toolchain.hightec-rt.com/

-The Arduino development environment add-in for Eclipse and the standard Arduino IDE:
ShieldBuddy TC375 Multicore IDE ver 1.93
www.hitex.co.uk/fileadmin/uk-files/downloads/ShieldBuddy/ShieldBuddyTC375IDE.zip

This Is my Code :

/*** Don't worry, the normal Arduino setup() and loop() are below this block! ***/
//#pragma GCC optimize "-O0"

/* DAM RAM uninitialised data */
StartOfUninitialised_DAMRam_Variables
/* Put your DAM RAM fast access variables that have no initial values here e.g. uint32 DAM_var; */
EndOfUninitialised_DAMRam_Variables

/* LMU uninitialised data */
StartOfInitialised_DAMRam_Variables
/* Put your DAM RAM fast access variables that have an initial value here e.g. uint32 DAM_var_init = 1; */
EndOfInitialised_DAMRam_Variables

/* If you do not care where variables end up, declare them here! */


/*** Core 0 ***/
int var;
String Vstring ;
void setup() {
// put your setup code for core 0 here, to run once:
var = 123456 ;
}


void loop() {
// put your main code for core 0 here, to run repeatedly:

Vstring = String(var) ;
Serial.println(Vstring);

}


/*** Core 1 ***/

/* CPU1 Uninitialised Data */
StartOfUninitialised_CPU1_Variables
/* Put your CPU1 fast access variables that have no initial values here e.g. uint32 CPU1_var; */
EndOfUninitialised_CPU1_Variables

/* CPU1 Initialised Data */
StartOfInitialised_CPU1_Variables
/* Put your CPU1 fast access variables that have an initial value here e.g. uint32 CPU1_var_init = 1; */
EndOfInitialised_CPU1_Variables

void setup1() {
// put your setup code for core 1 here, to run once:


}


void loop1() {
// put your main code for core 1 here, to run repeatedly:


}



/*** Core 2 ***/

/* CPU2 Uninitialised Data */
StartOfUninitialised_CPU2_Variables
/* Put your CPU2 fast access variables that have no initial values here e.g. uint32 CPU2_var; */
EndOfUninitialised_CPU2_Variables

/* CPU2 Initialised Data */
StartOfInitialised_CPU2_Variables
/* Put your CPU2 fast access variables that have an initial value here e.g. uint32 CPU2_var_init = 1; */
EndOfInitialised_CPU2_Variables


void setup2() {
// put your setup code for core 2 here, to run once:


}


void loop2() {
// put your main code for core 2 here, to run repeatedly:


}

/ **************************** /

My Error Message :

C:\Users\adm\AppData\Local\Temp\arduino_build_594295\sketch\sketch_oct08b.ino.cpp.o: In function `loop()':
sketch_oct08b:32: error: undefined reference to `String::operator=(String&&)'
collect2.exe: error: ld returned 1 exit status
exit status 1
undefined reference to `String::operator=(String&&)'

Does this device Aurix Shieldbuddy TC 375 , do not support String function classes.
If We Upload to my device Arduino Mega 2560 , It is not making Error .

Is there a solution?