Build libqalculate first
sudo apt-get install -y build-essential intltool libcurl4-openssl-dev libgtk-3-dev libxml2-dev
git clone https://github.com/Qalculate/libqalculate
cd libqalculate/
git checkout tags/v4.4.0
./autogen.sh
./configure --prefix=/opt/libqalculate
make
sudo make install
Build qalculate-gtk next
export PKG_CONFIG_PATH="$PKG_CONFIG_PATH:/opt/libqalculate/lib/pkgconfig"
git clone https://github.com/Qalculate/qalculate-gtk
cd qalculate-gtk/
git checkout tags/v4.4.0
./autogen.sh
./configure --prefix=/opt/qalculate-gtk
make
sudo make install
Links
sudo ln -s /opt/qalculate-gtk/bin/qalculate-gtk /usr/local/bin/qalculate-gtk
sudo rm -f /opt/qalculate-gtk/share/icons/hicolor/icon-theme.cache
sudo cp -r /opt/qalculate-gtk/share/icons/hicolor /usr/share/icons
sudo cp /opt/qalculate-gtk/share/applications/qalculate-gtk.desktop /usr/share/applications/
sudo update-icon-caches /usr/share/icons/*