As a workaround, you can back your wt to 9cb2319, compile pike, and then go back to HEAD to precompile with the pike you just built.
Re: Error building 8.1: test-pike not found
Marcus Comstedt (ACROSS) (Hail Ilpalazzo!) @ Pike (-) developers forum Fri, 27 May 2016 04:57:05 -0700