I noticed that we install the /usr/include/libunwind.h file, which can be picked by ports, but symbols from this header are defined in the /usr/lib/libgcc_eh.a static library. I find this a bit surprising.
If this header is intended to be public, then we should have libunwind.so in base, so that programs can link to it. Otherwise, we should hide the header and make ports use devel/libunwind or devel/llvmXY instead. Thoughts?