bazel 4.2 and 3.7 no longer building with native clang

[Steven Smith]

> I've conceded defeat to bazel. I've lost interest in the battle but I wish you luck if you wish to take it up...


My interest in bazel is the minimum necessary to get tensorflow-related projects working.

FWIW, bazel 5 builds and works on macOS, but previous versions do not, and I strongly doubt whether any magic selection of compiler will get them to work: https://github.com/bazelbuild/bazel/issues/15876

My takeaway is to avoid any version prior to version 5 (implying that the existing MacPorts bazel state is both broken and obsolete), and that only if absolutely necessary previous versions can be obtained from binary downloads from github.

Personally, I have also adopted the stance of avoiding bazel entirely unless absolutely necessary.

> On Jul 14, 2022, at 05:54, Chris Jones <jonesc at hep.phy.cam.ac.uk> wrote:
> 
> Hi
> 
>> On 13/07/2022 10:50 pm, Ryan Schmidt wrote:
>>> On Jul 13, 2022, at 11:46, Steven Smith wrote:
>>> How does one reconfigure the bazel Portfile to use a previous version of clang that has a chance of working to build previous versions of bazel, which are in turn necessary to build the tensor flow packages.
>> If certain compilers that MacPorts might choose will not build a port, add their names to compiler.blacklist and MacPorts will choose another compiler.
>> If you only want to exclude certain versions of a compiler (such as {clang < 700 >= 900}), include the compiler_blacklist_versions portgroup.
>> If you've excluded all compilers MacPorts might choose, add a suitable compiler to compiler.fallback.
> 
> This is all correct from the MacPorts side, but bazel is a different beast. It goes out of its way to not use the 'standard' ways of selecting compilers etc. That is why the bazel PG and portfile has all the convoluted logic it does to try and enforce the MP choice. I know this logic is fragile, it always has been.
> 
> Personally, I've conceded defeat to bazel. I've lost interest in the battle but I wish you luck if you wish to take it up...
> 
> Chris