The comments imply that you want to hint to the user that they should get (via some means) lld, glibc-static-devel and clang. But Suggests: will not help in this regard in any way. Suggests are only evaluated by the dependency resolver when there is an ambiguity in a transaction. E.g. if you would install rust, and for some reason a compiler would be required (but this could be satisfied by both gcc & clang) and there were an ambiguity between gcc and clang. In this case, the suggest would tell the dependency resolver to prefer clang. If clang is not part of the transaction, the Suggests is ignored.

Also, the suggest for clang & lld are not necessary, as there is a hard Requires for clang & lld a few lines above it.