Portable range check for *cursor_ value. (#4582)
Portable range check for *cursor_ value. (#4582)

Avoids the following compile error when char is unsigned:

error: comparison of unsigned expression >= 0 is always true [-Werror,-Wtautological-unsigned-zero-compare]
alexames/flatbuffers,stewartmiles/flatbuffers,pjulien/flatbuffers,google/flatbuffers,chenkai036/flatbuffers,rw/flatbuffers,google/flatbuffers,google/flatbuffers,stewartmiles/flatbuffers,royalharsh/flatbuffers,stewartmiles/flatbuffers,pjulien/flatbuffers,rw/flatbuffers,stewartmiles/flatbuffers,stewartmiles/flatbuffers,evolutional/flatbuffers,chenkai036/flatbuffers,stewartmiles/flatbuffers,royalharsh/flatbuffers,alexames/flatbuffers,google/flatbuffers,alexames/flatbuffers,alexames/flatbuffers,hgl888/flatbuffers,google/flatbuffers,evolutional/flatbuffers,google/flatbuffers,chenkai036/flatbuffers,evolutional/flatbuffers,alexames/flatbuffers,hgl888/flatbuffers,rw/flatbuffers,royalharsh/flatbuffers,stewartmiles/flatbuffers,DavadDi/flatbuffers,stewartmiles/flatbuffers,hgl888/flatbuffers,alexames/flatbuffers,rw/flatbuffers,evolutional/flatbuffers,stewartmiles/flatbuffers,evolutional/flatbuffers,alexames/flatbuffers,chenkai036/flatbuffers,rw/flatbuffers,royalharsh/flatbuffers,google/flatbuffers,google/flatbuffers,pjulien/flatbuffers,stewartmiles/flatbuffers,DavadDi/flatbuffers,royalharsh/flatbuffers,evolutional/flatbuffers,evolutional/flatbuffers,google/flatbuffers,chenkai036/flatbuffers,evolutional/flatbuffers,DavadDi/flatbuffers,evolutional/flatbuffers,stewartmiles/flatbuffers,alexames/flatbuffers,alexames/flatbuffers,evolutional/flatbuffers,evolutional/flatbuffers,rw/flatbuffers,rw/flatbuffers,pjulien/flatbuffers,royalharsh/flatbuffers,royalharsh/flatbuffers,google/flatbuffers,rw/flatbuffers,royalharsh/flatbuffers,alexames/flatbuffers,rw/flatbuffers,rw/flatbuffers,hgl888/flatbuffers,royalharsh/flatbuffers,alexames/flatbuffers,google/flatbuffers,chenkai036/flatbuffers,google/flatbuffers,pjulien/flatbuffers,alexames/flatbuffers,pjulien/flatbuffers,chenkai036/flatbuffers,stewartmiles/flatbuffers,hgl888/flatbuffers,alexames/flatbuffers,pjulien/flatbuffers,pjulien/flatbuffers,royalharsh/flatbuffers,alexames/flatbuffers,DavadDi/flatbuffers,evolutional/flatbuffers,hgl888/flatbuffers,chenkai036/flatbuffers,DavadDi/flatbuffers,google/flatbuffers,alexames/flatbuffers,DavadDi/flatbuffers,chenkai036/flatbuffers,pjulien/flatbuffers,rw/flatbuffers,evolutional/flatbuffers,stewartmiles/flatbuffers,rw/flatbuffers,pjulien/flatbuffers,google/flatbuffers,google/flatbuffers,chenkai036/flatbuffers,pjulien/flatbuffers,pjulien/flatbuffers