Hallo!
Yup, thanks for spotting that. That stuff is not used yet. That will be for compiling shared code as a separate dynamic library, so that things like Gem and PDP can be built as one-class-per-file libdir format. If you have a lot of shared code in PDContainer, then maybe you could try to get this working. Basically, you would build all the shared code into a pdcontainer.(so|dylib|dll), then each class as my_class.pd_extension. Each class would have to know how to find the shared library, but that shouldn't be too hard. Thomas Grill has built Flext like this.
Okay, I build now a shared library because I have a lot of shared code - it will be installed in the same directory as the pd externals.
But I am curious, if this also will compile on other platforms (now only tested on linux) ... ;)
LG Georg