odd problem testing libstdc++

[Brendan Kehoe]

I tried doing a build & check of libstdc++-v3 as part of an egcs build tree,
but found every test was failing with unresolved refs to `__throw@@GCC_3.0'
and the like.

Looking in the test log, I found that the compiler wasn't able to find
libgcc_s.so.  Odd.  I finally got around it by explicitly setting up
LD_LIBRARY_PATH in my environment to point to the gcc build directory.  It's
unclear to me why dejagnu didn't tack in the necessary rpath, like it does for
the shared libstdc++ library.

At any rate, that's the missing bit I think: if libgcc_s.so exists in the gcc
build tree that's providing the g++ driver and other pieces, that directory
should get added to a usage of rpath for the linker.

Hope this helps,
B