Merge dashpay#6199: fix: compile error due to rebase mistake between b…

…itcoin#22937 and ipc/process

540f687 fix: lock `::cs_main` before accessing `ChainstateManager::m_best_header` (Kittywhiskers Van Gogh)
aafded6 fix: compilation error due to rebase error between bitcoin#22937 and ipc/process (Kittywhiskers Van Gogh)

Pull request description:

  ## Issue being fixed or feature implemented
  CI failure for multiprocess

  ## What was done?
  It resolve compilation failure on develop (apply changes from 22937 to ipc/process)

  See alternate solutions:
   - dashpay#6192
   - dashpay#6195

  ## How Has This Been Tested?
  Run build locally:
  ```
  make MULTIPROCESS=1 -j10
  ./configure --prefix=$(pwd)/depends/x86_64-pc-linux-gnu --enable-suppress-external-warnings --enable-werror    --enable-debug --enable-crash-hooks  --enable-maintainer-mode --enable-stacktraces  --enable-multi-process
  ```

  ## Breaking Changes
  N/A

  ## Checklist:
  - [x] I have performed a self-review of my own code
  - [ ] I have commented my code, particularly in hard-to-understand areas
  - [ ] I have added or updated relevant unit/integration/functional/e2e tests
  - [ ] I have made corresponding changes to the documentation
  - [x] I have assigned this pull request to a milestone

ACKs for top commit:
  PastaPastaPasta:
    utACK 540f687

Tree-SHA512: 75b675e93763e8e53086a10b93516b8ec94418902f9be2de738517176cc835c0dad25c286426089a5327a9c13d1787b89debda2c6025cb598489204d7d5af2cf

src/dsnotificationinterface.cpp

@@ -79,7 +79,7 @@ void CDSNotificationInterface::UpdatedBlockTip(const CBlockIndex *pindexNew, con
     if (pindexNew == pindexFork) // blocks were disconnected without any new ones
         return;
 
-    m_mn_sync.UpdatedBlockTip(m_chainman.m_best_header, pindexNew, fInitialDownload);
+    m_mn_sync.UpdatedBlockTip(WITH_LOCK(::cs_main, return m_chainman.m_best_header), pindexNew, fInitialDownload);
 
     // Update global DIP0001 activation status
     fDIP0001ActiveAtTip = pindexNew->nHeight >= Params().GetConsensus().DIP0001Height;

src/ipc/process.cpp

@@ -30,8 +30,8 @@ class ProcessImpl : public Process
         return mp::SpawnProcess(pid, [&](int fd) {
             fs::path path = argv0_path;
             path.remove_filename();
-            path.append(new_exe_name);
-            return std::vector<std::string>{path.string(), "-ipcfd", strprintf("%i", fd)};
+            path /= fs::PathFromString(new_exe_name);
+            return std::vector<std::string>{fs::PathToString(path), "-ipcfd", strprintf("%i", fd)};
         });
     }
     int waitSpawned(int pid) override { return mp::WaitProcess(pid); }