[Pre-RFC] target-glibc: Proposal to add native support for GLIBC versions for the -gnu targets

comex:

For a more substantive point: It’s odd that you propose two different ways to specify the glibc deployment target (triple suffix and -C argument), especially when they are both different from how Apple deployment targets are specified (environment variable).

Triple suffix is to support the approach zig-build uses today, which should simplify migration. IMHO, the -C target-glibc:X.Y and the config file are the proper approach.

As you mentioned, the MacOS env variable is hacky, and I do not think that following that path is the right way to handle this feature.

In other words, I would suggest picking one new mechanism, and adding support for it for both glibc and Apple targets.

Making that change for Apple is a bit of a stretch for this RFC (and completely irrelevant for the stub libs part).