* src/gpgme.h.in (gpgme_query_swdb_result_t): New.
(gpgme_op_query_swdb): New.
(gpgme_op_query_swdb_result): New.
* src/libgpgme.vers, src/gpgme.def: Add the two new functions.
* src/queryswdb.c: New.
* src/Makefile.am (main_sources): Add new file.
* src/context.h (OPDATA_QUERY_SWDB): New.
* src/engine-backend.h (struct engine_ops): Add field 'query_swdb'.
Adjust all initializer.
* src/engine.c (_gpgme_engine_op_query_swdb): New.
* src/engine-gpgconf.c (parse_swdb_line): New.
(gpgconf_query_swdb): New.
(_gpgme_engine_ops_gpgconf): Register that function.
* src/util.h (GPG_ERR_TOO_OLD): Define for older libgpg-error.
(GPG_ERR_ENGINE_TOO_OLD): Ditto.
* tests/run-swdb.c: New.
* tests/Makefile.am (noinst_PROGRAMS): Add new debug tool.