Comment 33 for bug 311029

Here is how to build curl with libssl support for Ubuntu 18.04. LTS:

sudo apt-get install build-essential debhelper libssh-dev
sudo apt-get source curl
sudo apt-get build-dep curl

cd curl-*

sudo patch < ~/Downloads/ubuntu_libssl.patch

sudo dpkg-buildpackage -uc -us
# -us Do not sign the source package.
# -uc Do not sign the .changes file.

cd ..

sudo dpkg -i curl_*.deb
sudo dpkg -i libcurl3-*.deb
sudo dpkg -i libcurl3-gnutls_*.deb

sudo apt-mark hold curl
sudo apt-mark hold libcurl3
sudo apt-mark hold libcurl3-gnutls
# sudo apt-mark unhold <package-name>

Hope that helps somebody.