if exists(global.xcomp)
  set global.xcomp = 0
else
  global xcomp = 0

echo >"0:/user/xcomp.g" "if exists(global.xcomp)"
echo >>"0:/user/xcomp.g" "  set global.xcomp = 0"
echo >>"0:/user/xcomp.g" "else"
echo >>"0:/user/xcomp.g" "  global xcomp = 0"