Assuming it's the general endowment fund, no it isn't spoken for. In fact, many schools are criticized because they don't use their endowments toward anything other than as a a means of showing what an impressive school they are. It's said that many schools with
endowments over 1 billion could allow students to attend for free or at greatly reduced rates just from a portion of the investment earnings on the endowment, but choose to reinvest those earnings instead. The only way donors can ensure their donations are being spent and not being held onto is by making a special purpose endowment, like toward a professorship, or in Paterno's case, the library. But special purpose endowments that come with restrictions on how the money is spent aren't usually considered part of the general endowment fund.
Penn State is rich enough to be able to fund their other sports without football and without becoming "a MAC school," although as I've noted above, there are MAC schools that compete for national championships without a big time football program.