Feather M4 Express compilation problem with Servo library

Hello,

I'm using a Adafruit Feather M4 Express board. When I tried to use the Arduino Servo library it didn't compile.
I have these errors repeated in the whole Servo.cpp file:

Arduino : 1.8.7 (Linux), Carte : "Adafruit Feather M4 Express (SAMD51), Enabled"

/home/rafaelle/Arduino/libraries/Servo/src/samd/Servo.cpp: In function 'void Servo_Handler(timer16_Sequence_t, Tc*, uint8_t, uint8_t)':
/home/rafaelle/Arduino/libraries/Servo/src/samd/Servo.cpp:44:60: error: 'volatile struct TC_STATUS_Type::<anonymous>' has no member named 'SYNCBUSY'
 #define WAIT_TC16_REGS_SYNC(x) while(x->COUNT16.STATUS.bit.SYNCBUSY);
                                                            ^

/home/rafaelle/Arduino/libraries/Servo/src/samd/Servo.cpp: In function 'void _initISR(Tc*, uint8_t, uint32_t, IRQn_Type, uint8_t, uint8_t)':
/home/rafaelle/Arduino/libraries/Servo/src/samd/Servo.cpp:123:11: error: 'struct Gclk' has no member named 'CLKCTRL'
     GCLK->CLKCTRL.reg = (uint16_t) (GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK0 | GCLK_CLKCTRL_ID(gcmForTimer));
           ^

/home/rafaelle/Arduino/libraries/Servo/src/samd/Servo.cpp:124:18: error: 'struct Gclk' has no member named 'STATUS'
     while (GCLK->STATUS.bit.SYNCBUSY);
                  ^
/home/rafaelle/Arduino/libraries/Servo/src/samd/Servo.cpp:134:30: error: 'TC_CTRLA_WAVEGEN_NPWM' was not declared in this scope
     tc->COUNT16.CTRLA.reg |= TC_CTRLA_WAVEGEN_NPWM;
                              ^
exit status 1

I don't know how solve this.

I would be very thankful if i get some hints,

Regards Rafou