-O4 limitations in llvm/llvm-gcc-4.2 2.5?

Chris,
   Thanks for the hint. Moving over the libLTO.dylib
from llvm 2.5 solved all of the linkage errors. I was
able to completely build xplor-nih at -O4 now. The
core xplor and xplor-tcl testsuite show no regressions.
I do get 7 testcases in the xplor-python testsuite
failing with bus errors now. The xplor-tcl and xplor-python
tests are all run by tcl and python respectively loading
their xplor-nih modules. I would assume that the shared
libraries created at -O4 should look like just any other
shared library to MacOS X and that shared modules built
at -O4 should be loadable from programs like python and
tcl that aren't built with -O4, right?
                Jack
ps Interestingly PR3376 goes latent at -O4.