Add conlyopts and cxxopts attributes to cc rules

[keith]

The inability to pass C or C++ specific compiler flags to targets that
contain a mix of those sources is a common sticking point for new users.
These mirror the global --conlyopt and --cxxopt flags but at the
target level.

Fixes #22041

RELNOTES: Add conlyopts and cxxopts attributes to cc rules

[davidben]

Thank you! I'm not familiar enough with Bazel to review this, but this would solve a ton of problems with Bazel that prevent BoringSSL from using it effectively. We support many build systems, and issue alone, due to all the problems it causes down the line, is probably singlehandedly the reason why it is the most expensive build system for us to support right now. E.g. we'd also be able to enable parse_headers because #23460 would be moot. If this could be merged and then cherry-picked into every release branch that can take it, that would be lovely.

[comius]

LGTM from Blaze perspective.

I want LGTM also from @trybka, before merging.

[fmeum]

@bazel-io fork 7.4.0

[trybka]

LGTM. I am extremely supportive.

[Wyverald]

@keith: could you add a RELNOTES line to the PR description? I'll attach it during import.

[keith]

done!

[Wyverald]

FTR, this is breaking Google-internal tests because some other code is calling cc_helper.get_copts, and is not happy about the new param. What makes it worse is that this code is not in @_builtins, so there's version skew.

Could you perhaps make the new param optional?

[keith]

made it optional