Steps to reproduce

I am posting this as a bug rather than a build error because although the problem appears when building a package, it was caused by a recent commit to spack, not the package itself (I narrowed it down to commit 330832c, authored by @trws )

$ spack install [email protected]

This command will fail, with g++ complaining that it doesn't know -Wthread-safety (I reproduced it on 3 platforms with various versions of gcc).

The leveldb package wasn't changed. I looked at its cmake file and the weird thing is that it has a mechanism that checks whether this flag is supported (here: https://github.com/google/leveldb/blob/1.22/CMakeLists.txt#L53) so I don't know if spack is interfering with it in some way.

Error message

No response

Information on your system

• Spack: 0.18.0.dev0 (330832c)
• Python: 3.9.5
• Platform: linux-ubuntu21.04-sandybridge
• Concretizer: clingo

General information

• I have run spack debug report and reported the version of Spack/Python/Platform
• I have searched the issues of this repo and believe this is not a duplicate
• I have run the failing commands in debug mode and reported the output