BLD: Don't require gfortran on windows.
BLD: Don't require gfortran on windows.

bartosh/zipline,florentchandelier/zipline,humdings/zipline,magne-max/zipline-ja,quantopian/zipline,alphaBenj/zipline,wilsonkichoi/zipline,quantopian/zipline,florentchandelier/zipline,Scapogo/zipline,bartosh/zipline,wilsonkichoi/zipline,magne-max/zipline-ja,humdings/zipline,enigmampc/catalyst,Scapogo/zipline,alphaBenj/zipline,enigmampc/catalyst