[tlbuild] luaharfbuzz breaks tostring

[Simon Dales]

On Fri, 2020-03-06 at 09:48 +0000, Simon Dales wrote:
> ////////////////////
> function show_var(K,V)
...

Prettier version:
///////////////
function show_var(K,V)
  io.write('//' .. K .. '\n')
  local io_write_fixed = function(V,Len)
    io.write(string.sub(V .. string.rep(' ',Len),1,Len))
  end
  for k,v in pairs(V) do
    io_write_fixed('  ' .. k .. ':',20)
    io_write_fixed(type(v) .. ':',10)
    io.write('"')
--    io.write(tostring(v))
    io.write(p_tostring(v))
    io.write('"')
    io.write('\n')
  end
end
///////////////

Simon