Using `-undefined dynamic_lookup` ?

[Peter Danecek]

Hi MacPorts Developers,

This is related to my last question on building Fortran extensions using `numpy.distutils`. But this one is quite short.

So I figured how to workaround my problem by specifying some extra arguments in the setup.py script. But I have (at least) two option. One is to link against the python library explicitly (using the link in ${prefix}/lib, the other which is actually used by all C extension is the `-undefined dynamic_lookup`. Given the fact that it is used for the C extensions and seems to be usual in the context of Python (e.g. when building manually etc.), I am inclined to use the second one. But I am a bit wondering if this is completely save, or if there might be situations where this would result in using the wrong library, for example the systems python library. 

Any thoughts on that?

BTW: 
I still would like to understand why there is this difference in the linking step for Fortran extension vs. C extensions and why all this works out of the box when used manually but not with MacPorts.