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

[Ellis Hoag via llvm-commits]

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@@ -1095,6 +1095,14 @@ defm tail_merge_strings
     : BB<"tail-merge-strings", "Enable string tail merging",
          "Disable string tail merging to improve link-time performance">,
       Group<grp_rare>;
+def slop_scale_eq
+    : Joined<["--"], "slop_scale=">,
+      MetaVarName<"<unsigned_int>">,
+      HelpText<"Specify the slop scale. Default value is 256. If your binary "
+               "has too many consec branch instructions resulting in "
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ellishg wrote:

```suggestion
               "has too many consecutive branch instructions resulting in "
```

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