When compiling without external signer support, the resulted `bench_bitcoin.exe` fails on Windows:
```
>.\bench_bitcoin.exe -filter=AddrManSelectByNetwork
Error: bad optional access
```

Steps to reproduce the failure:
- cross compiling on Ubuntu 22.04:
```
$ make -j $(nproc) -C depends HOST=x86_64-w64-mingw32 NO_QT=1
$ ./autogen.sh
$ ./configure CONFIG_SITE=$PWD/depends/x86_64-w64-mingw32/share/config.site --disable-external-signer
$ make -j $(nproc)
```
- compiling natively on Windows:

Apply the diff as follows:
```diff
--- a/build_msvc/bitcoin_config.h.in
+++ b/build_msvc/bitcoin_config.h.in
@@ -41,9 +41,6 @@
 /* Define this symbol to enable ZMQ functions */
 #define ENABLE_ZMQ 1
 
-/* define if external signer support is enabled (requires Boost::Process) */
-#define ENABLE_EXTERNAL_SIGNER /**/
-
 /* Define to 1 if you have the declaration of `be16toh', and to 0 if you
    don't. */
 #define HAVE_DECL_BE16TOH 0
```
Then
```
>py -3 build_msvc\msvc-autogen.py
>msbuild build_msvc\bitcoin.sln -property:Configuration=Release -verbosity:minimal
>src\bench_bitcoin.exe -filter=AddrManSelectByNetwork
Error: bad optional access
```

---

The failure does not manifest itself when running `bench_bitcoin.exe` using Wine on Linux.
if (!pid) {
        BOOST_CHECK_EQUAL(close(fd[1]), 0); 
        TestOtherProcess(dirname, lockname, fd[0]);
    }
    BOOST_CHECK_EQUAL(close(fd[0]), 0); 
#endif
    
    BOOST_CHECK_EQUAL(LockDirectory(dirname, lockname), false);
    fs::create_directories(dirname);
    
    BOOST_CHECK_EQUAL(LockDirectory(dirname, lockname, true), true);
    
    BOOST_CHECK_EQUAL(LockDirectory(dirname, lockname), true);
    
    BOOST_CHECK_EQUAL(LockDirectory(dirname, lockname), true);
    
    bool threadresult;
    std::thread thr(TestOtherThread, dirname, lockname, &threadresult);
    thr.join();
    BOOST_CHECK_EQUAL(threadresult, true);
#ifndef WIN32
    
    char ch;
    BOOST_CHECK_EQUAL(write(fd[1], &LockCommand, 1), 1);
    BOOST_CHECK_EQUAL(read(fd[1], &ch, 1), 1);
    BOOST_CHECK_EQUAL((bool)ch, false);
    
    ReleaseDirectoryLocks();
    
    BOOST_CHECK_EQUAL(LockDirectory(dirname, lockname, true), true);