* src/context.h (gpgme_context): Add 'request_origin'.
* src/gpgme.c (gpgme_release): Free that field.
(gpgme_set_ctx_flag, gpgme_get_ctx_flag): Add "request-origin".
* src/engine-backend.h (engine_ops): Add 'set_engine_ops' func ptr and
adjust all users.
* src/engine.c (_gpgme_engine_set_engine_flags): New.
* src/op-support.c (_gpgme_op_reset): Call that func.
* src/engine-gpg.c (struct engine_gpg): Add 'request_origin'.
(gpg_set_engine_flags): New.
(_gpgme_engine_ops_gpg): Hook it.
(build_argv): Use command line option --request-origin.
* src/engine-gpgsm.c (struct engine_gpgsm): Add 'request_origin'.
(gpgsm_set_engine_flags): New.
(_gpgme_engine_ops_gpgsm): Hook it.
(start): Send OPTION "request-origin".
* src/engine-assuan.c (struct engine_llass): Add 'request_origin'.
(gpgsm_set_engine_flags): New.
(_gpgme_engine_ops_assuan): Hook it.
(start): Send OPTION "pretend-request-origin".