"il faut"
is the il/elle at the present time for the verb "Faillir" and "Falloir"
But their meaning are totally different.
Fallir : to fail something
Falloir : it is when you have to do something, express a need
As a french people, I never read or say the verb "Faillir" at the present time.
And i didn't know it was also "il faut".
So everytime, you can read or hear "il faut": it will always be the "Falloir" verb that express something that you have/need to do.