How to solve this segmentation fault?

Hi,
How to solve this segmentation fault? Thanks

```
-- local hdf5 = require('hdf5')

local threads = require 'threads'

threadPool = threads.Threads(3, function(threadid) require('hdf5') end )
-- threadPool = threads.Threads(3)

for i = 1, 10 do
threadPool:addjob(function() local a = hdf5.open(i .. '.hdf5','w'); a:close() end )
end

threadPool:synchronize()
threadPool:terminate()
```

Start by reproducing the segmentation fault with the Lua snippet, comparing the two Thread construction variants and the require('hdf5') calls inside and outside the thread initializer. Trace the thread and HDF5 interaction to identify the failure, then document a verified workaround or fix and confirm that the loop completes without crashing.

Written by the indexing model from the issue text.