x509_cert_pubkey: windows build fix
x509_cert_pubkey: windows build fix

move declaration to the top to fix windows

leecrest/luacrypto,mkottman/luacrypto,mkottman/luacrypto,aryajur/luacrypto,leecrest/luacrypto,hp-sam/luacrypto-1,hp-sam/luacrypto-1,aryajur/luacrypto