[lld] [lld-macho]Define a flag for adjusting slop scale (PR #164295)

[Ellis Hoag via llvm-commits]

================
@@ -1995,6 +1995,15 @@ bool link(ArrayRef<const char *> argsArr, llvm::raw_ostream &stdoutOS,
                    OPT_no_separate_cstring_literal_sections, false);
   config->tailMergeStrings =
       args.hasFlag(OPT_tail_merge_strings, OPT_no_tail_merge_strings, false);
+  if (auto *arg = args.getLastArg(OPT_slop_scale_eq)) {
+    StringRef v(arg->getValue());
+    unsigned slop = 0;
+    if (!llvm::to_integer(v, slop, 0))
+      error(arg->getSpelling() +
+            ": expected a non-negative integer, but got '" + arg->getValue() +
----------------
ellishg wrote:

```suggestion
            ": expected a non-negative integer, but got '" + v +
```
Might as well use the stringref variable

https://github.com/llvm/llvm-project/pull/164295