Revert renaming of tools to exec_tools

[Flamefire]

Reverts part of f827c02 as that causes trouble due to action_env variables not passed through to any dependent build which breaks builds using TF_SYSTEM_LIBS

Fixes #43019

[mihaimaruseac]

Let's hold on this one, Bazel folks are investigating at the moment whether we need to use tools or exec_tools.

[Flamefire]

Sure. Just to highlight what I found:

• Using tools instead makes action_env be passed to builds triggered further down the dependency chain, with exec_tools they are not
• Some code which was affected by the tools->exec_tools renaming in 2.3 has since been changed to (IIRC) use _local_genrule. I'm unsure how to verify that action_envs are passed through that.
• There was some discussion in Bazel about introducing host_env variables similar to action_env. I'm not sure I could follow that distinction as e.g. for us the whole build is executed on the local machine, so in that case those 2 (if there were 2) should be equal. At best by default
• It is absolutely essential to have a way to pass variables like CPATH, LIBRARY_PATH and the like (not speaking of PATH and LD_LIBRARY_PATH which seem be to passed through already) to all invocations without exception or stuff breaks.

Hope that helps in resolving this. In the meantime this patch is used by us to build TF on our HPC systems

[gbaned]

@mihaimaruseac Any update on this PR? Please. Thanks!

[mihaimaruseac]

No update yet from the Bazel team

[Flamefire]

Any update yet? As for

whether we need to use tools or exec_tools

For the build using system protobuf using exec_tools does not work but tools does. For the non-system protobuf either work. So IMO this is a step forward and discussion which should be used could be done in a follow-up issue and likely depends on bugfix or feature addition on the Bazel side because at the current state exec_tools cannot be the correct choice if it breaks builds.

[mihaimaruseac]

Approving though it might be reverted if things fail