llvm 3.0 (tags/Apple/clang-211.12) (based on LLVM 3.0svn) segfault
The version of clang which ships with xcode 4 Apple Lion segfaulted with the smoke test on the head of the trunk. Robin found that a linux compile of the head of the clang++ trunk passed the smoke test. The segfault is likely a bug in the 3.0 series of clang++ or due to something Apple did to llvm. Tests show that xcode clang++ can run c10 successfully.
xcode clang++ passes the smoke test when compiled in debug mode, or when compiled in optimized mode and run under valgrind. The valgrind run shows no problems.
Matt traced the start of the segfault to the removal of an unused variable at line 52 of coolheavy.h. In r5822 c5177 was added back and llvm now passes cleanly. Valgrind and the test suite are ok.
This behaves like a bug in Apple clang++.
Revisit when the clang++ gets the next major xcode update.