Fix clang-tidy modernize-use-bool-literals warnings in headers

src/Func.h

@@ -351,7 +351,7 @@ public:
 protected:
     BuiltinFunc() {
         func = nullptr;
-        is_pure = 0;
+        is_pure = false;
     }
 
     built_in_func func;

src/analyzer/protocol/http/HTTP.h

@@ -44,7 +44,7 @@ public:
     bool Undelivered(int64_t len);
     int64_t BodyLength() const { return body_length; }
     int64_t HeaderLength() const { return header_length; }
-    void SkipBody() { deliver_body = 0; }
+    void SkipBody() { deliver_body = false; }
     const std::string& FileID() const { return precomputed_file_id; }
 
 protected:

src/analyzer/protocol/smtp/SMTP.h

@@ -50,7 +50,7 @@ public:
     void ConnectionFinished(bool half_finished) override;
     void Undelivered(uint64_t seq, int len, bool orig) override;
 
-    void SkipData() { skip_data = 1; } // skip delivery of data lines
+    void SkipData() { skip_data = true; } // skip delivery of data lines
 
     static analyzer::Analyzer* Instantiate(Connection* conn) { return new SMTP_Analyzer(conn); }
 

src/broker/Data.h

@@ -323,7 +323,7 @@ public:
     /**
      * Converts the value to a Boolean.
      */
-    [[nodiscard]] bool ToBool(bool fallback = 0) const noexcept {
+    [[nodiscard]] bool ToBool(bool fallback = false) const noexcept {
         if ( auto val = broker::get_if<bool>(value_); val ) {
             return *val;
         }