gpgsm: New option --require-compliance
* sm/gpgsm.c (oRequireCompliance): New. (opts): Add --require-compliance. (main): Set option. * sm/gpgsm.h (opt): Add field require_compliance. (gpgsm_errors_seen): Declare. * sm/verify.c (gpgsm_verify): Emit error if non de-vs compliant. * sm/encrypt.c (gpgsm_encrypt): Ditto. * sm/decrypt.c (gpgsm_decrypt): Ditto.