This seems to be a big problem with a lot of other projects so I'm surprised it hasn't been reported here yet.
I'm getting make errors like so...
/usr/include/openssl/ec.h:1039:16: note: forward declaration of 'ECDSA_SIG {aka struct ECDSA_SIG_st}'
typedef struct ECDSA_SIG_st ECDSA_SIG;
Is there a fix for this?