mpi: Add function gcry_mpi_set_opaque_copy.
* src/gcrypt.h.in (gcry_mpi_set_opaque_copy): New. * src/visibility.c (gcry_mpi_set_opaque_copy): New. * src/visibility.h (gcry_mpi_set_opaque_copy): Mark visible. * src/libgcrypt.def, src/libgcrypt.vers: Add new API. * tests/mpitests.c (test_opaque): Add test.
- Signed-off-by: Werner Koch <wk@gnupg.org>