[llvm] Reapply "Allow "[[FLAGS=<none>]]" value in the ELF Fileheader Flags field (#143845)" (PR #151094)

[James Henderson via llvm-commits]

================
@@ -281,7 +281,8 @@ template <class ELFT> Expected<ELFYAML::Object *> ELFDumper<ELFT>::dump() {
   Y->Header.Type = Obj.getHeader().e_type;
   if (Obj.getHeader().e_machine != 0)
     Y->Header.Machine = ELFYAML::ELF_EM(Obj.getHeader().e_machine);
-  Y->Header.Flags = Obj.getHeader().e_flags;
+  if (Obj.getHeader().e_flags != 0)
+    Y->Header.Flags = ELFYAML::ELF_EF(Obj.getHeader().e_flags);
----------------
jh7370 wrote:

> This cast will ensure we generate a Flags output everytime.

This doesn't seem to make much sense to me. The line above it (`e_flags != 0`) will ensure we don't generate a Flags field if the value is 0 (and that is the behaviour we want).

So, what is the cast doing and could you give an example where the behaviour has changed with this case, please?

https://github.com/llvm/llvm-project/pull/151094