Update GnuTLS for JHBuild

I am trying to compile GTK+ from source and have installed JHBuild for this purpose. I've already managed to build PyGObject using JHBuild and the sanitycheck runs without output. For building GTK+ it seems that JHBuild needs GnuTLS >= version 3.0 as it states in the terminal: checking for GNUTLS... no configure: error: in `/home/xiaolong/jhbuild/releases/gnome-apps-3.17.90/glib-networking-2.45.1': configure: error: "Requested 'gnutls >= 3.0' but version of GnuTLS is 2.12.23 You may find new versions of GnuTLS at http://www.gnu.org/software/gnutls/ " See `config.log' for more details *** Error during phase configure of glib-networking: ########## Error running ./configure --prefix /home/xiaolong/jhbuild/releases/gnome-apps-3.17.90/install --enable-installed-tests --disable-static --disable-gtk-doc --disable-Werror *** [13/29] So I searched and found the following instructions on how to build GnuTLS in a more recent version than installed on my system: http://www.bauer-power.net/2014/06/how-to-install-gnutls-3123-from-source.html I needed to install some libraries to complete the instructions without errors, but that's done. Now I thought JHBuild would surely run fine until the next error in the build process of GTK+, but that wasn't the case. Instead I still see the same error message about requiring a version >= 3.0 of GnuTLS. It seems JHBuild has a problem locating the GnuTLS build from source and still finds the one installed from the package management system instead. How do I fix this behavior?