gpgsm: New option --compatibility-flags.
* sm/gpgsm.c (oCompatibilityFlags): New option. (compatibility_flags): new. (main): Parse and print them in verbose mode. * sm/gpgsm.h (opt): Add field compat_glags.: (COMPAT_ALLOW_KA_TO_ENCR): New. * sm/keylist.c (print_capabilities): Take care of the new flag. * sm/certlist.c (cert_usage_p): Ditto. * common/miscellaneous.c (parse_compatibility_flags): New. * common/util.h (struct compatibility_flags_s): New.
Backported-from-master: f0b373cec93bb01f02b9c0a3ab1f3e242b381c3f
Backported-from-master: ce63eaa4f8f3f41aafcaddd8d658dacd522334a8