(go): copy unsafe.go to unsafe_appengine.go
(go): copy unsafe.go to unsafe_appengine.go

MiCHiLU/flatbuffers,MiCHiLU/flatbuffers,MiCHiLU/flatbuffers,MiCHiLU/flatbuffers,MiCHiLU/flatbuffers,MiCHiLU/flatbuffers,MiCHiLU/flatbuffers,MiCHiLU/flatbuffers