Usage of facebook Folly

Question

I'm on MacOS and with g++-11. Folly successfully builds and when I try to run a piece of code from the test file executors/test/ExecutorWithPriorityTest.cpp, the compiler says

/Users/tannyxie/Documents/Project Preparation/github/folly_include/installed/folly/include/folly/FBString.h:2753:8: error: 'fmt' has not been declared
 2753 | struct fmt::formatter<folly::fbstring> : private formatter<fmt::string_view> {
      |        ^~~
/Users/tannyxie/Documents/Project Preparation/github/folly_include/installed/folly/include/folly/FBString.h:2753:22: error: expected unqualified-id before '<' token
 2753 | struct fmt::formatter<folly::fbstring> : private formatter<fmt::string_view> {
      |                      ^

This is the code I run.

#include <folly/executors/ExecutorWithPriority.h>
  
#include <folly/executors/CPUThreadPoolExecutor.h>
#include <folly/futures/Future.h>
#include <folly/portability/GTest.h>

using namespace folly;

int main() {
  bool tookLopri = false;
  auto completed = 0;
  auto hipri = [&] {
    EXPECT_FALSE(tookLopri);
    completed++;
  };
  auto lopri = [&] {
    tookLopri = true;
    completed++;
  };
  auto pool = std::make_shared<CPUThreadPoolExecutor>(
      0 /*numThreads*/, 2 /*numPriorities*/);
  {
    auto loPriExecutor = ExecutorWithPriority::create(
        getKeepAliveToken(pool.get()), Executor::LO_PRI);
    auto hiPriExecutor = ExecutorWithPriority::create(
        getKeepAliveToken(pool.get()), Executor::HI_PRI);
    for (int i = 0; i < 50; i++) {
      loPriExecutor->add(lopri);
    }
    for (int i = 0; i < 50; i++) {
      hiPriExecutor->add(hipri);
    }
    pool->setNumThreads(1);
  }
  pool->join();
}

I compiled it with command g++-11 folly.cpp.

Am I missing any header file? Or should I add some command line flag?