centos6 だと epel の libev が古くてめんどくさくなったので centos7 でビルドした。
sudo yum groupinstall "Development Tools"
sudo yum install libev libev-devel zlib zlib-devel openssl openssl-devel git
git clone [email protected]:tatsuhiro-t/nghttp2.git
cd nghttp2
autoreconf -i
automake
autoconf
./configure
make
sudo make install
/usr/local/bin/{nghttp,nghttpd,nghttpx} が入る