CCS reports errors related to tiva function UARTStdioConfig()

Hello,

This is my code:

#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include "utils/uartstdio.h"
#include "inc/hw_memmap.h"
#include "inc/hw_gpio.h"
#include "inc/hw_types.h"
#include "inc/hw_ints.h"
#include "driverlib/interrupt.h"
#include "driverlib/pin_map.h"
#include "driverlib/gpio.h"
#include "driverlib/uart.h"
#include "driverlib/sysctl.h"



void onButtonDown(void);
void UART_Init(void);

void main()
{
	SysCtlClockSet(SYSCTL_SYSDIV_4| SYSCTL_USE_PLL | SYSCTL_OSC_INT | SYSCTL_XTAL_16MHZ);

	SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);
	GPIOPinTypeGPIOInput(GPIO_PORTF_BASE, GPIO_PIN_4);
	GPIOPadConfigSet(GPIO_PORTF_BASE, GPIO_PIN_4,GPIO_STRENGTH_2MA, GPIO_PIN_TYPE_STD_WPU);
	GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, GPIO_PIN_1);

	GPIOIntDisable(GPIO_PORTF_BASE, GPIO_PIN_4);
	GPIOIntClear(GPIO_PORTF_BASE, GPIO_PIN_4);
	GPIOIntRegister(GPIO_PORTF_BASE, onButtonDown);
	GPIOIntTypeSet(GPIO_PORTF_BASE, GPIO_PIN_4, GPIO_FALLING_EDGE);
	GPIOIntEnable(GPIO_PORTF_BASE, GPIO_PIN_4);

	UART_Init();

	while (1)
	{
		//GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_1, (GPIOPinRead(GPIO_PORTF_BASE, GPIO_PIN_1) ^ GPIO_PIN_1));
		SysCtlDelay(1000000);
	}
}

void onButtonDown(void)
{
	GPIOIntDisable(GPIO_PORTF_BASE, GPIO_PIN_4);
	GPIOIntClear(GPIO_PORTF_BASE, GPIO_PIN_4);
	SysCtlDelay(500000);
	GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_1, (GPIOPinRead(GPIO_PORTF_BASE, GPIO_PIN_1) ^ GPIO_PIN_1));
	GPIOIntClear(GPIO_PORTF_BASE, GPIO_PIN_4);
	GPIOIntEnable(GPIO_PORTF_BASE, GPIO_PIN_4);
}

void UART_Init(void)
{
    //
    // Enable GPIO port A which is used for UART0 pins.
    // TODO: change this to whichever GPIO port you are using.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);

    //
    // Configure the pin muxing for UART0 functions on port A0 and A1.
    // This step is not necessary if your part does not support pin muxing.
    // TODO: change this to select the port/pin you are using.
    //
    GPIOPinConfigure(GPIO_PA0_U0RX);
    GPIOPinConfigure(GPIO_PA1_U0TX);

    //
    // Enable UART0 so that we can configure the clock.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);

    //
    // Use the internal 16MHz oscillator as the UART clock source.
    //
    UARTClockSourceSet(UART0_BASE, UART_CLOCK_PIOSC);

    //
    // Select the alternate (UART) function for these pins.
    // TODO: change this to select the port/pin you are using.
    //
    GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);

    //
    // Initialize the UART for console I/O.
    //
    UARTStdioConfig(0, 115200, 16000000); //here I get the error, when I comment this line the error disapears
}

And these are the errors reported:

When I add the file uartstdio.c into the project directory, the error is gone. But the compiler must search for this file as it does for the others. I don't understand what is wrong. Any help would be much appreciated.