How do I e-file with charitable stock donation, as Turbotax is requiring a cost basis to complete form 8283? Turbotax won't let me submit if I leave it blank.

I don't know the cost basis on the charitable donation, as that's not reported anywhere. And the date of acquired shares are over multiple dates >1 year ago, which the IRS does not require cost basis to be reported. If I mark it as 0, Turbotax eliminates the donation deduction.