gpg: Add option --dirmngr-program.
* g10/gpg.c: Add option --dirmngr-program. * g10/options.h (struct opt): Add field dirmngr_program. * g10/call-dirmngr.c (create_context): Use new var. * dirmngr/dirmngr.c: Include gc-opt-flags.h. (main): Remove GC_OPT_FLAG_*. * tools/gpgconf-comp.c (GC_OPT_FLAG_NO_CHANGE): Move macro to ... * common/gc-opt-flags.h: here.