Hello Stuart,

Here is what I would suggest you try.

1) On line 20 of SConstruct change
env.Append(LIBS = ['niftiio', 'znz', 'z'])

to

env.Append(LIBS = ['niftiio', 'znz', 'z', 'm'])

If that does not fix the problem

2) Please upgrade gcc to 4.7.2 from your 4.4.x

Let me know how it goes and if you have any questions after trying these steps.

Best,
Nagesh