core: Check for GPG_TTY as well as DISPLAY.
* src/engine-assuan.c (llass_new): Update --ttyname from GPG_TTY. * src/engine-g13.c (g13_new): Ditto. * src/engine-gpg.c (gpg_new): Ditto. * src/engine-uiserver.c (uiserver_new): Ditto. * src/engine-gpgsm.c (gpgsm_new): Ditto.
Useful when no DISPLAY is set and there is no attached terminal to the
current process.
- Signed-off-by: Ben Kibbey <bjk@luxsci.net>