[llvm] [libc][bazel] Mark socket functions weak (PR #115088)

[Alexey Samsonov via llvm-commits]

vonosmas wrote:

Right, I agree with Nick's comment that we probably don't want to blanket-define all functions as weak. I do think we need to let Bazel build downstream users decide which functions should be made weak, however -- but let's postpone this update to `libc_function` logic to future changes. OK with this for now.

https://github.com/llvm/llvm-project/pull/115088