[Pyrex] C-API implementation in Pyrex 0.9.6

[Stefan Behnel]

Stefan Behnel wrote:
>> I forgot to mention that this uses a package local import, so the first lines
>> of lxml/objectify.pyx look like this:
>>
>>     from etree cimport _Document, _Element, ElementBase
>>     from etree cimport _ElementIterator, ElementClassLookup
>>     from etree cimport elementFactory, textOf
>>     cimport etree as cetree
> 
> I think the problem here is that __Pyx_ImportModule() does not take the
> current package into account. I'll fix it to first try an import based on the
> package of the current module and then try a global import.

I also think that Pyrex should not re-import a module for each type it wants
to cimport from it, but rather import each required module once, store it in a
global variable, and reuse it whenever it is accessed by generated code. I'll
see if I can fix this while I'm at it.

Note that I'm fixing this in the merged Cython, but it shouldn't be too hard
to transmogrify the fix for plain Pyrex.

Stefan