Require fails - Error in ffi.lua

I get the following error:

``` lua
th> require 'hdf5'
...e/fabrice/torch/install/share/lua/5.1/trepl/init.lua:384: ...ome/fabrice/torch/install/share/lua/5.1/hdf5/ffi.lua:56: expected align(#) on line 579 stack traceback:
...e/fabrice/torch/install/share/lua/5.1/trepl/init.lua:501: in function <...e/fabrice/torch/install/share/lua/5.1/trepl/init.lua:494>
[C]: in function 'error'
...e/fabrice/torch/install/share/lua/5.1/trepl/init.lua:384: in function 'require'
[string "_RESULT={require 'hdf5'}"]:1: in main chunk
[C]: in function 'xpcall'
...e/fabrice/torch/install/share/lua/5.1/trepl/init.lua:652: in function 'repl'
.../torch/install/lib/luarocks/rocks/trepl/scm-1/bin/th:199: in main chunk
[C]: ?
```

Running Lua 5.1
Could it be that ffi.lua needs LuaJIT? If so, how could I work around that? LuaJIT has some kind of memory limit that makes the network I am trying to run unusable.

OS:

```
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.1 LTS
Release: 16.04
Codename: xenial
```

Installation of torch-hdf5 is successful.

Packages related to hdf5 installed:

```
$ dpkg -l | grep 'hdf5'
ii hdf5-helpers 1.8.16+docs-4ubuntu1 amd64 Hierarchical Data Format 5 (HDF5) - Helper tools
ii hdf5-tools 1.8.16+docs-4ubuntu1 amd64 Hierarchical Data Format 5 (HDF5) - Runtime tools
ii libhdf5-10:amd64 1.8.16+docs-4ubuntu1 amd64 Hierarchical Data Format 5 (HDF5) - runtime files - serial version
ii libhdf5-cpp-11:amd64 1.8.16+docs-4ubuntu1 amd64 Hierarchical Data Format 5 (HDF5) - C++ libraries
ii libhdf5-dev 1.8.16+docs-4ubuntu1 amd64 Hierarchical Data Format 5 (HDF5) - development files - serial version
ii libhdf5-serial-dev 1.8.16+docs-4ubuntu1 all transitional dummy package

```

```
$ luarocks list
Warning: Failed loading manifest for /home/fabrice/.luarocks/lib/luarocks/rocks: /home/fabrice/.luarocks/lib/luarocks/rocks/manifest: No such file or directory

Installed rocks:
----------------

argcheck
scm-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

audio
0.1-0 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

cunn
scm-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

cunnx
scm-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

cutorch
scm-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

cwrap
scm-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

dok
scm-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

env
scm-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

fftw3
scm-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

gnuplot
scm-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

graph
scm-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

graphicsmagick
1.scm-0 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

hdf5
0-0 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

image
1.1.alpha-0 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

lua-cjson
2.1devel-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

luabitop
1.0.2-3 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

luaffi
scm-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

luafilesystem
1.6.3-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

nn
scm-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

nngraph
scm-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

nnx
0.1-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

optim
1.0.5-0 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

paths
scm-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

penlight
scm-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

qtlua
scm-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

qttorch
scm-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

signal
scm-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

sundown
scm-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

sys
1.1-0 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

threads
scm-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

torch
scm-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

totem
0-0 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

trepl
scm-1 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks

xlua
1.0-0 (installed) - /home/fabrice/torch/install/lib/luarocks/rocks
```

Start by reproducing `require 'hdf5'` with Lua 5.1 and inspect `hdf5/ffi.lua` at line 56, especially the declaration around line 579 that reports the missing `align(#)`. Compare the behavior with the installed LuaJIT-related packages and determine whether the project supports plain Lua 5.1; done means the supported runtime or a verified workaround is established and documented.

Written by the indexing model from the issue text.