json: Use gpgrt_argparse instead of argsparse.c
* src/gpgme-json.c: Remove header argparse.h. Define GPGRT_ENABLE_ARGPARSE_MACROS. (interactive_repl): Replace strusage by gpgrt_strusage. (my_strusage): Add SPDX level. (main): Switch to gpgrt_argparse stuff but keep very limited functionality when building with an older libgpg-error.
- Signed-off-by: Werner Koch <wk@gnupg.org>