[llvm] [ThinLTO] Allow importing based on a workload definition (PR #74545)

[Teresa Johnson via llvm-commits]

================
@@ -138,6 +139,9 @@ static cl::opt<bool>
     ImportAllIndex("import-all-index",
                    cl::desc("Import all external functions in index."));
 
+static cl::opt<std::string> WorkloadDefinitions("thinlto-workload-def",
----------------
teresajohnson wrote:

Add comment describing this option, and the expected format of the specified file.

https://github.com/llvm/llvm-project/pull/74545