back X11-cairo dependencies

Probably we should enable headless back.

Author: rmottola

.github/scripts/dependencies.sh

@@ -10,7 +10,7 @@ install_prerequisites() {
     sudo apt-get install -y cmake pkg-config libgnutls28-dev libgmp-dev libffi-dev libicu-dev \
 	 libxml2-dev libxslt1-dev libssl-dev libavahi-client-dev zlib1g-dev \
 	 libjpeg-dev libtiff-dev libpng-dev \
-	 libfreetype-dev
+	 libfreetype-dev libxt-dev libcairo2-dev
 
     if [ $LIBRARY_COMBO = 'gnu-gnu-gnu' ];
     then