[Fatal Error] Kernel.h@27,10: 'chrono' file not found

I’m getting the compiler-result:
[Fatal Error] Kernel.h@27,10: ‘chrono’ file not found

I moved the following declarations and definitions thereof into separate mx.h and mx.h files

/* Private variables ---------------------------------------------------------/
DFSDM_Channel_HandleTypeDef hdfsdm1_channel1;
I2C_HandleTypeDef hi2c2;
QSPI_HandleTypeDef hqspi;
SPI_HandleTypeDef hspi3;
UART_HandleTypeDef huart1;
UART_HandleTypeDef huart3;
PCD_HandleTypeDef hpcd_USB_OTG_FS;
/
Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_DFSDM1_Init(void);
static void MX_I2C2_Init(void);
static void MX_QUADSPI_Init(void);
static void MX_SPI3_Init(void);
static void MX_USART1_UART_Init(void);
static void MX_USART3_UART_Init(void);
static void MX_USB_OTG_FS_PCD_Init(void);

Try including stdlib.h and test.