Update to 310:

    * update package/freebsd files based on xterm #309 port.
    * adapt  changes  from  Minux3.2  which  ported  xterm #197, to allow
      building  on  that  platform  both using imake as well as using the
      configure script.
    * update precompose.c based on Unicode 7.0
    * build-fix for --with-Xaw3dxft option (report by Emanuel Haupt).

(wiz)