Merge #20530: lint, refactor: Update cppcheck linter to c++17 and improve explicit usage

1e62350ca20898189904a88dfef9ea11ddcd8626 refactor: Improve use of explicit keyword (Fabian Jahr)
c502a6dbfb854ca827a5a3925394f9e09d29b898 lint: Use c++17 std in cppcheck linter (Fabian Jahr)

Pull request description:

  I found the `extended-lint-cppcheck` linter still uses `std=c++11` when reviewing #20471. The only difference in the output after this change is one line is missing:

  ```
  src/script/descriptor.cpp:159:5: warning: Struct 'PubkeyProvider' has a constructor with 1 argument that is not explicit. [noExplicitConstructor]
  ```

  After some digging, I am still not sure why this one is ignored with c++17 when 40 other`noExplicitConstructor` warnings were still appearing.

  In the second commit, I fix these warnings, adding `explicit` where appropriate and adding fixes to ignore otherwise.

ACKs for top commit:
  practicalswift:
    cr ACK 1e62350ca20898189904a88dfef9ea11ddcd8626: patch looks correct!
  MarcoFalke:
    review ACK 1e62350ca20898189904a88dfef9ea11ddcd8626

Tree-SHA512: dff7b324429a57160e217cf38d9ddbb6e70c6cb3d3e3e0bd4013d88e07afc2292c3df94d0acf7122e9d486322821682ecf15c8f2724a78667764c05d47f89a12

2 files changed, 3 insertions, 3 deletions

diff --git a/src/wallet/bdb.h b/src/wallet/bdb.h
index 9073c1b6b3..4f97665f08 100644
--- a/src/wallet/bdb.h
+++ b/src/wallet/bdb.h
@@ -56,7 +56,7 @@ public:
     std::unordered_map<std::string, WalletDatabaseFileId> m_fileids;
     std::condition_variable_any m_db_in_use;
 
-    BerkeleyEnvironment(const fs::path& env_directory);
+    explicit BerkeleyEnvironment(const fs::path& env_directory);
     BerkeleyEnvironment();
     ~BerkeleyEnvironment();
     void Reset();
diff --git a/src/wallet/scriptpubkeyman.h b/src/wallet/scriptpubkeyman.h
index 43791acfcf..cec46a0fbb 100644
--- a/src/wallet/scriptpubkeyman.h
+++ b/src/wallet/scriptpubkeyman.h
@@ -172,7 +172,7 @@ protected:
     WalletStorage& m_storage;
 
 public:
-    ScriptPubKeyMan(WalletStorage& storage) : m_storage(storage) {}
+    explicit ScriptPubKeyMan(WalletStorage& storage) : m_storage(storage) {}
     virtual ~ScriptPubKeyMan() {};
     virtual bool GetNewDestination(const OutputType type, CTxDestination& dest, std::string& error) { return false; }
     virtual isminetype IsMine(const CScript& script) const { return ISMINE_NO; }
@@ -504,7 +504,7 @@ class LegacySigningProvider : public SigningProvider
 private:
     const LegacyScriptPubKeyMan& m_spk_man;
 public:
-    LegacySigningProvider(const LegacyScriptPubKeyMan& spk_man) : m_spk_man(spk_man) {}
+    explicit LegacySigningProvider(const LegacyScriptPubKeyMan& spk_man) : m_spk_man(spk_man) {}
 
     bool GetCScript(const CScriptID &scriptid, CScript& script) const override { return m_spk_man.GetCScript(scriptid, script); }
     bool HaveCScript(const CScriptID &scriptid) const override { return m_spk_man.HaveCScript(scriptid); }