[clang] [InstallAPI] Pick up input headers by directory traversal (PR #94508)

[Zixu Wang via cfe-commits]

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@@ -97,6 +97,14 @@ class HeaderFile {
                                           Other.Excluded, Other.Extra,
                                           Other.Umbrella);
   }
+
+  bool operator<(const HeaderFile &Other) const {
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zixu-w wrote:

What's the reasoning for the ordering? Might be easier to understand in the future with some comments.

https://github.com/llvm/llvm-project/pull/94508