GNUstep support in PyObjC

WARNING: GNUStep support is broken. If you would like to help, let us know.

PyObjC has limited support for GNUstep, the 'objc' and 'Foundation' packages build and pass some, but by far not all, unittests. More work is needed to make the GNUstep port as stable as the Mac OS X "port".

The GNUstep port was primarily developed on Linux i86 (specifically the Debian testing distribution), using python 2.3.3, gcc 3.3.2 and gnustep-base1 1.9.0-1. The code in setup.py works for this configuration, but probably not for other configurations.

GNUstep support is very fragile, in some versions of the the selectors for new classes should be strings, in others they should be SEL objects (as you would expect). We also use undocumented private functions to initialize new classes.

TODO

• [Serious] Fix linkage problems. The ObjC runtime doesn't seem to be initialized correctly and/or the classes in newly loaded frameworks are not correctly registered in the runtime.
• Fix the odd bug...

  I currently get the following text when importing objc:

  Unable to retrieve information about SIGPIPE
  

  This text is not printed by PyObjC and I haven't been able to find who does print that text...

• Fix bugs found using the unittests

  runPyObjCTests finds some problems that disappear when those tests are run separately...

• Extract more CFLAGS and LDFLAGS information from the GNUstep build system, instead of hard-coding the information