You can also use curl --negotiate -u : for kerberos (provided curl is built with it and spengo). curl supports quite a few less used auth methods, but OP ment

You can also use curl --negotiate -u : for kerberos (provided curl is built with it and spengo). curl supports quite a few less used auth methods, but OP mentioned custom headers, not basic auth per se, (thats why I used Authentication instead of WWW-Authenticate or Authorization as an example)