Revert r263622, "clang/lib/Frontend/ModuleDependencyCollector.cpp: Use clang/Config/config.h instead of llvm's."
Revert r263622, "clang/lib/Frontend/ModuleDependencyCollector.cpp: Use clang/Config/config.h instead of llvm's."

I'll commit better fix(es) later. "llvm/Config/config.h" shouldn't be available here.

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@263623 91177308-0d34-0410-b5e6-96231b3b80d8

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