[libcxx] [libcxxabi] [libunwind] [llvm] [runtimes] Probe for -nostdlib++ and -nostdinc++ with the C compiler (PR #108357)

[Martin Storsjö via cfe-commits]

mstorsjo wrote:

> > Actually this PR is the case of https://lab.llvm.org/buildbot/#/builders/164/builds/3908, not #113491
> 
> Sorry about that.
> 
> Are you able to dig up any of the cmake configure logs from these builds, so that we can figure out how this ends up breaking things? Because as in most of these cases, the visible output in the buildbot logs mostly say that some configure checks end up going the wrong way, but we can't really see why.

@vitalybuka Are you able to pull out some details to help figure out what this really broke here?

https://github.com/llvm/llvm-project/pull/108357