Log Message:
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).