[clang] [clang][modules-driver] Add dependency scan and dependency graph (PR #152770)

[Naveen Seth Hanig via cfe-commits]

naveen-seth wrote:

Hmm, this is odd.
`pthread_create`, ` pthread_...` are called from within the C++ Standard library.
This should be linked by default.

I also developed this PR using `-DBUILD_SHARED_LIBS=ON` and had no issue, neither has any BuildBot failed because of this.
I'll be able to investigate this further today evening if I have more information.

Is `pthread` installed and availabe on your system?

```bash
ldconfig -p | grep pthread
``

@mikaelholmen 

https://github.com/llvm/llvm-project/pull/152770