DSA_SIG_new() allocates and initializes a DSA_SIG structure.
DSA_SIG_free() frees the DSA_SIG structure and its components. The
values are erased before the memory is returned to the system.
RETURN VALUES
If the allocation fails, DSA_SIG_new() returns NULL and sets an
error code that can be obtained by
ERR_get_error(3). Otherwise it returns a pointer
to the newly allocated structure.