Merge bitcoin/bitcoin#24104: fs: Make compatible with boost 1.78

dc5d6b0d4793ca978f71f69ef7d6b818794676c2 fs: Make compatible with boost 1.78 (Andrew Chow)

Pull request description:

  Boost 1.78 removed `operator+` in a way that breaks our usage of it in a subclass. A [proposed workaround](https://github.com/boostorg/filesystem/issues/223#issuecomment-1000230207) for this is to cast the argument to `boost::filesystem::path`, and this is backwards compatible with older versions of boost.

  Additionally, it appears that `fs::canonical` no longer removes trailing slashes. This was causing a test to fail. The solution is to explicitly remove the trailing separator in the one place that `fs::canonical` is used.

  Lastly, `fs::create_directories` now has an error message saying `create_directories` instead of `create_directory`. This caused wallet_multiwallet.py to fail. The error message check has been updated to be able accept either string.

  Fixes #23846

ACKs for top commit:
  ryanofsky:
    Code review ACK dc5d6b0d4793ca978f71f69ef7d6b818794676c2
  vincenzopalazzo:
    ACK https://github.com/bitcoin/bitcoin/pull/24104/commits/dc5d6b0d4793ca978f71f69ef7d6b818794676c2

Tree-SHA512: d4d8e7b49b8dfbf0ced9bfe9a2b3827841227fc755fc799f19159076b0ccf882432cc8b6ad93cdeda98fb58b942b9ba50a9e0a6b4f6b1e0097e80f1074ae5682

2 files changed, 2 insertions, 2 deletions

diff --git a/src/fs.h b/src/fs.h
index 9f18794539..bc36636084 100644
--- a/src/fs.h
+++ b/src/fs.h
@@ -88,7 +88,7 @@ static inline auto quoted(const std::string& s)
 // Allow safe path append operations.
 static inline path operator+(path p1, path p2)
 {
-    p1 += std::move(p2);
+    p1 += static_cast<boost::filesystem::path&&>(p2);
     return p1;
 }
 
diff --git a/src/wallet/load.cpp b/src/wallet/load.cpp
index 2d47673705..e6f96074d5 100644
--- a/src/wallet/load.cpp
+++ b/src/wallet/load.cpp
@@ -29,7 +29,7 @@ bool VerifyWallets(WalletContext& context)
         fs::path wallet_dir = fs::PathFromString(args.GetArg("-walletdir", ""));
         boost::system::error_code error;
         // The canonical path cleans the path, preventing >1 Berkeley environment instances for the same directory
-        fs::path canonical_wallet_dir = fs::canonical(wallet_dir, error);
+        fs::path canonical_wallet_dir = fs::canonical(wallet_dir, error).remove_trailing_separator();
         if (error || !fs::exists(wallet_dir)) {
             chain.initError(strprintf(_("Specified -walletdir \"%s\" does not exist"), fs::PathToString(wallet_dir)));
             return false;