* src/estream.c (do_close): Add arg 'cancel_mode' and chnage all
callers.
(_gpgrt_fcancel): New.
* src/gpg-error.def.in, src/gpg-error.vers: Add function.
* src/visibility.c (gpgrt_fcancel): New.
* src/gpg-error.h.in (gpgrt_fcancel): New.