There are a lot of software which requires openssl/ec.h and openssl.ecdsa.h by default. The openssl "bindist" flag (it is off by default) disables EC due to some legal issues. However, it seems possible to enable it partially at least. For example, it was enabled in RedHat back in 2013: https://bugzilla.redhat.com/show_bug.cgi?id=319901 Please consider enabled it in Gentoo as well.
we've already reviewed the patches used in fedora and found them untenable. it isn't merely passing a "foo" flag to the configure script. *** This bug has been marked as a duplicate of bug 531540 ***