My change in bb3915149a7c9b1660db9caebfc96343352e8454 added a call to std::time which worked generally as there must be some transitive include of <ctime>. However, I saw one MSVC bot failure: InstrProfWriter.cpp(202): error C2039: 'time': is not a member of 'std' from https://lab.llvm.org/buildbot/#/builders/63/builds/2325. Presumably explictly including <ctime> should fix this.