* src/gpg-error.h.in (GPGRT_NVC_SECTION): New.
* src/name-value.c (_gpgrt_name_value_container): Add section_mode.
(_gpgrt_nvc_new): Set it.
(_gpgrt_nvc_get_flag): Return it.
(valid_name): Add arg sectionmode and change callers.
(do_nvc_parse): Parse section names in section mode.
(_gpgrt_nvc_write): Return an error in section mode.