JavaFX/OpenJFX is included in Oracle JDK 8 but not in OpenJDK 8 bundled for server deployments. Adding the gt-javafx module to the full -Dall build breaks the build on OpenJDK wherever OpenJFX is not installed, including the new Jenkins on build.geoserver.org and GeoSolutions OpenJDK Jenkins. On Debian amd64 this requires 19 MB of downloads and 52 MB on disk. Because OpenJDK is a supported platform, I think that this new native dependency requires discussion. I will remove javafx from the full -Dall build until agreement is reached.
gt-javafx can still be built with the -Pjavafx profile. I changed the name for consistency.
On Debian or derivatives, OpenJFX can be installed with: apt-get install openjfx
OpenJDK 8 on Debian sid amd64