[lld] [ELF] Add support for PT_OPENBSD_NOBTCFI (PR #120005)

[Fangrui Song via llvm-commits]

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@@ -2405,6 +2405,13 @@ Writer<ELFT>::createPhdrs(Partition &part) {
     addHdr(PT_GNU_STACK, perm)->p_memsz = ctx.arg.zStackSize;
   }
 
+  if (ctx.arg.osabi == ELFOSABI_OPENBSD) {
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MaskRay wrote:

The osabi check can be deleted as zNoBtCfi cannot be true for other osabi values

https://github.com/llvm/llvm-project/pull/120005