[llvm] [BPF] Use ".L" local prefix label for basic blocks (PR #95103)

[via llvm-commits]

4ast wrote:

> > The bpf asm code is often read my humans and extra dot is a visual noise.
> 
> basic block labels would no longer be added to the symbol table

that's a regression. they didn't meant to be in symbol table.

> Would removing the dot from private global symbols be an option, so that they are prefixed with `L` instead `.L`?

Yep. PrivateGlobalPrefix =  PrivateLabelPrefix = "L" is certainly better.

https://github.com/llvm/llvm-project/pull/95103