net/bitcoin: secp256k1_ecdh.h

[0x6a73]

Hello. I've found out that bitcoin package in ports supplies secp256k1.h and 
secp256k1_recovery.h, but not secp256k1_ecdh.h. I need it in order to compile a 
library required to run Zeronet. Is it a bug or was it not supplied with the 
package intentionally?