If you want a version of openssl compiled with the enable-ec_nistp_64_gcc_128 option and you are using Gentoo Linux, you can grab it from my overlay:
layman -f layman -a hnaparst emerge openssl
The new flag "nist" is turned on by default. I have 1.0.1i and 1.0.2_beta2 in the overlay.
Hope it helps.