[lld] [LLD] Add CLASS syntax to SECTIONS (PR #95323)

[Peter Smith via llvm-commits]

https://github.com/smithp35 commented:

I've not taken a look at the code in detail yet. Will hope to do that over the coming week. I've limited myself to commenting on some of the syntax and error messages.

I do like the idea of having ways of controlling a section match without needing a full output section.

One potential use case is matching `SHT_NOBITS` sections generated from `__attribute__((section(.bss.<name>)))` quite often these want to be placed after the `*.bss` input section description but `*.bss.*` will match every section generated this way.
 

https://github.com/llvm/llvm-project/pull/95323