message: llvm2alive: check libfn is available in given platform
diff: @@ -47,7 +47,7 @@ known_call(llvm::CallInst &i, const llvm::TargetLibraryInfo &TLI,
  auto decl = i.getCalledFunction();
  llvm::LibFunc libfn;
  - if (!decl || !TLI.getLibFunc(*decl, libfn))
  + if (!decl || !TLI.getLibFunc(*decl, libfn) || !TLI.has(libfn))
  return { nullptr, false };
  switch (libfn) {
  