Sounds like the project contains a typo: "--no-undefined" should be "-no-undefined" (one leading hyphen, not two). Sounds like that's what #32268 was supposed to have fixed. Maybe there's more than one occurrence of the problem.
Python modules (e.g. py26-pynifti) ignore configure.compiler and instead use the compiler that was used to compile the corresponding python port (e.g. python26) so manually overriding configure.compiler when building a python module has no effect.
Manually adding configure.cxx when setting the compiler to apple-gcc-4.2 has not been necessary since the release of MacPorts 2.0.4; if we still have documentation somewhere saying this is necessary, please let us know where so that we can correct it.