Example, Microsoft has rewritten their C standard library in C++ with extern "C" entry points.

Yes. Microsoft have made a number of silly mistakes with respect to OS design, which has cost them the server space outside of authentication for your and my lifetime. Bloat is not the answer to either security or performance problems.

Quite the contrary, I admire Microsoft for being one of the first companies to start driving C away from our IT stacks.

Thankfully Apple, Google, IBM and Unisys seem to be on the same boat.

And llvm-libc may be one such implementation: https://llvm.org/docs/Proposals/LLVMLibC.html

That's a pipe dream, not an implementation. Let's wait until it actually happens before getting too excited, and then we be actually able to evaluate the drawbacks.

> Current Status - llvm-libc development is still in the planning phase.