llvm-gcc-4.2 Build Problems

Still working on the validator buildbot as I can.

Now I'm tackling what appears to be a configure problem for llvm-gcc-4.2.

Here's the configure log:

../src/configure
--prefix=/ptmp/dag/buildbot/slaves/llvm-validate/llvm-validate-release-kentsfield-linux/build/install
--program-prefix=llvm-
--enable-llvm=/ptmp/dag/buildbot/slaves/llvm-validate/llvm-validate-release-kentsfield-linux/build/llvm-initial/obj
--enable-languages=c,c++

creating cache ./config.cache
checking host system type... config.sub: missing argument
Try `config.sub --help' for more information.

checking target system type... config.sub: missing argument
Try `config.sub --help' for more information.

checking build system type... config.sub: missing argument
Try `config.sub --help' for more information.

checking for a BSD compatible install... /usr/bin/install -c
checking whether ln works... yes
[...]

This eventually leads to a failure to find genmodes during boostrap so
everything blows up.

If I run this in the shell, it appears to work fine. More strangely, this
only fails on release builds. A debug build buildbot finishes just fine.

Anyone seen anything like this before?

                                -Dave