Allow inspecting LLVM code during imaging mode (JuliaLang#36974)

src/aotcompile.cpp

@@ -867,6 +867,11 @@ void *jl_get_llvmf_defn(jl_method_instance_t *mi, size_t world, char getwrapper,
  Function *F = NULL;
  if (m) {
  // if compilation succeeded, prepare to return the result
+ // For imaging mode, global constants are currently private without initializer
+ // which isn't legal. Convert them to extern linkage so that the code can compile
+ // and will better match what's actually in sysimg.
+ for (auto &global : output.globals)
+ global.second->setLinkage(GlobalValue::ExternalLinkage);
  if (optimize)
  PM->run(*m.get());
  const std::string *fname;