Diffusion GpgOL c1085f44e177

Make async encryption optional

Authored by aheinecke on Jul 23 2018, 9:31 AM.

Description

Make async encryption optional

* src/common_indep.h (opt): Add sync_enc.
* src/mail.cpp (Mail::isAsynCryptDisabled_o): Respect it.
* src/main.c (read_options): Read it.

If we have users where GpgOL crashes on send we or the
user might want to disable async encryption.