The wdt.c has a WDT_resetTimer function:
//*****************************************************************************
//
//! Clears the timer counter of the Watchdog Timer.
//!
//! \param baseAddress is the base address of the WDT module.
//!
//! This function clears the watchdog timer to 0x0000h.
//!
//! \return None
//
//*****************************************************************************
void WDT_resetTimer (unsigned int baseAddress)
However, there is no function prototype for WDT_resetTimer in wdt.h
wdt.h contains the following prototype, for which there is no corresponding function in wdt.c
extern void WDT_clearCounter (unsigned int baseAddress);
Therefore, when using driverlib had to call WDT_resetTimer but that causes the compiler to generate a "function declared implicitly" warning.
Request that the driverlib be changed to provide the correct function prototype to remove the warning.