[Factor-builds] mason on windows-x86-64: build loop error

[<sl...@fa...>]

Fatal error on windows7-64

The I/O operation has been aborted because of either a thread exit or an application request.
(U) Quotation: [ set-namestack init-catchstack self quot>> call -> stop ]
(O) Word: build-loop
(O) Word: update-sources
(O) Word: git-pull
(O) Word: try-output-process
(O) Word: (stream-contents-by-element)
(O) Method: M\ decoder stream-read1
(O) Word: decode-char/predicate-engine
(O) Method: M\ input-port stream-read1
(O) Method: M\ windows (wait-to-read)
(O) Word: twiddle-thumbs
(O) Method: M\ object throw
(U) Quotation: [
        OBJ-CURRENT-THREAD special-object error-thread set-global
        continuation -> error-continuation set-global
        [ original-error set-global ] [ rethrow ] bi
    ]