To my knowledge there isn't an implementation of `sse4.2` that doesn't have `crc32`.
The Clang driver also sets `crc32` to be implicitly enabled when an explicit `-crc32`
wasn't provided. This matches that behaviour.
We need this behaviour to compile libraries like `rocksdb` which currently guard against
`crc32` intrinsics by checking for `sse4.2`.
The compiler actually doesn't need any functional changes for this: Sema
does reification based on the tag indices of `std.builtin.Type` already!
So, no zig1.wasm update is necessary.
This change is necessary to disallow name clashes between fields and
decls on a type, which is a prerequisite of #9938.
* some manual fixes to generated CPU features code. In the future it
would be nice to make the script do those automatically.
* add to various target OS switches. Some of the values I was unsure of
and added TODO panics, for example in the case of spirv CPU arch.
