[clang] [clang][DependencyScanning] Track modules that resolve from sysroot. (PR #130634)

[Ben Langmuir via cfe-commits]

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@@ -835,6 +850,13 @@ void ModuleDepCollectorPP::addAllSubmoduleDeps(
   });
 }
 
+void ModuleDepCollectorPP::addClangModule(const Module *M, const ModuleID ID,
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benlangmuir wrote:

How about something like "addOneModuleDep"?  If find it hard to guess from the name how this is different from e.g. `addModuleDep` which also has a similar signature. 

https://github.com/llvm/llvm-project/pull/130634