key.cpp:729:106: error: cannot convert ‘unsigned char*’ to ‘const secp256k1_context_t* {aka const secp256k1_context_struct*}’ for argument ‘1’ to ‘int secp256k1_ec_pubkey_tweak_add(const secp256k1_context_t*, unsigned char*, int, const unsigned char*)’
     bool ret = secp256k1_ec_pubkey_tweak_add((unsigned char*)pubkeyChild.begin(), pubkeyChild.size(), out);
                                                                                                          ^
make: *** [obj/key.o] Error 1