lldb_{10, 11}: polish the cmakeFlags

[ggreif]

Motivation for this change

• pass LLVM_ENABLE_RTTI directly, not as an environment variable
• LLDB_CODESIGN_IDENTITY, is ignored on Darwin

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

[ggreif]

@GrahamcOfBorg build lldb_10 lldb_11

[7c6f434c]

Diff makes sense to me. Not realistically going to build/test this any time soon.

[ggreif]

@primeos what about these? Let me squash, quick.

[DieGoldeneEnte]

Why do you disable RTTI for lldb? I think it would make more sense to enable it, since it is enabled for llvm/clang.

[ggreif]

It was disabled before, I didn't change that. What would enabling buy us? LLVM has its own RTTI-ish scheme, and it doesn't need all the features of the C++ RTTI. Or am I missing a detail?

[DieGoldeneEnte]

It is set for llvm, because some packages seem to need it (4731485)and it is set on clang, because a mismatch can lead to problems with clang-plugins.
I don't know if it changes something for lldb, I just think it makes sense to keep it the same everywhere (at least where it is needed/given).

[ggreif]

I know a (Rust) program that uses lldb.so, but it will never care. If other C++ programs want to link against it that in a way that RTTI would become advantageous, I would say let's enable. Otherwise it just increases .so sizes.

[primeos]

LGTM, thanks :)

Feel free to continue that RTTI discussion (or open an issue/PR) but since it was already disabled this PR should be good to go regardless.

[DieGoldeneEnte]

I don't know of any programs using lldb in this way, but it leads to linking errors that are hard to track.

I only asked, because it is different from llvm. I'll have another look at it later, maybe RTTI isn't needed anymore, quite some time has passed since it was enabled :)