You do not need a form 1099-B to report the sale. And the IRS does not require 1099-B forms as long as you have records of cost basis and sale price, date of acquisition and date of sale. The capital gains/losses are long term if you have held the stocks for more than a year.
On form 8949, these transactions will be reported in Box F - Long term transactions not reported to you on Form 1099-B.
The instructions for form 8949 say:
Box F.
Report on a Part II with box F checked all long-term transactions for which you can't check box D or E because you didn't receive a Form 1099-B (or substitute statement).