Use flags

 * Found these USE flags for x11-base/xorg-server-1.19.6:
 U I
 - - debug       : Enable extra debug codepaths, like asserts and extra output. If you want to get meaningful backtraces see
                   https://wiki.gentoo.org/wiki/Project:Quality_Assurance/Backtraces
 - - dmx         : Build the Distributed Multiheaded X server
 - - doc         : Add extra documentation (API, Javadoc, etc). It is recommended to enable per package instead of globally
 + + glamor      : Enable Glamor OpenGL 2D acceleration
 + + ipv6        : Add support for IP version 6
 - - kdrive      : Build the kdrive X servers
 - - libressl    : Use dev-libs/libressl as SSL provider (might need ssl USE flag), packages should not depend on this USE flag
 - - minimal     : Install a very minimal build (disables, for example, plugins, fonts, most drivers, non-critical features)
 - - static-libs : Build static versions of dynamic libraries as well
 + + suid        : Enable setuid root program, with potential security risks
 - - systemd     : Enable use of systemd-specific libraries and features like socket activation or session tracking
 - - tslib       : Build with tslib support for touchscreen devices
 + + udev        : Enable virtual/udev integration (device discovery, power and storage device support, etc)
 - - unwind      : Enable libunwind usage for backtraces
 - - wayland     : Enable dev-libs/wayland backend
 - - xcsecurity  : Build Security extension
 - - xephyr      : Build the Xephyr server
 - - xnest       : Build the Xnest server
 + + xorg        : Build the Xorg X server (HIGHLY RECOMMENDED)
 - - xvfb        : Build the Xvfb server