fix: use literal true/false constants for bool conversion

- nlohmann_json 3.12 can construct from literal true/false
- Use ternary operator to select between json(true) and json(false)
- Works around the explicit bool constructor restriction

Author: timblaktu

src/v2/pdf_resources/page_cell.h

@@ -186,9 +186,9 @@ namespace pdflib
       cell.push_back(font_name); // 18
 
       // Work around nlohmann_json 3.12 explicit bool constructor
-      // Use brace initialization to explicitly construct from bool
-      cell.push_back(nlohmann::json{widget}); // 19
-      cell.push_back(nlohmann::json{left_to_right}); // 20
+      // Must use ternary to select pre-constructed boolean values
+      cell.push_back(widget ? nlohmann::json(true) : nlohmann::json(false)); // 19
+      cell.push_back(left_to_right ? nlohmann::json(true) : nlohmann::json(false)); // 20
     }
     assert(cell.size()==header.size());
 

src/v2/pdf_sanitators/cells.h

@@ -124,8 +124,8 @@ namespace pdflib
 	  item["rendering_mode"] = cell.rendering_mode;
 
 	  // Work around nlohmann_json 3.12 explicit bool constructor
-	  item["widget"] = nlohmann::json{cell.widget};
-	  item["left_to_right"] = nlohmann::json{cell.left_to_right};
+	  item["widget"] = cell.widget ? nlohmann::json(true) : nlohmann::json(false);
+	  item["left_to_right"] = cell.left_to_right ? nlohmann::json(true) : nlohmann::json(false);
 	}
 
 	result.push_back(item);

src/v2/qpdf/to_json.h

@@ -163,8 +163,8 @@ namespace pdflib
           {
             bool val = obj.getBoolValue();
             // Work around nlohmann_json 3.12 explicit bool constructor
-            // Use brace initialization to explicitly construct from bool
-            result = nlohmann::json{val};
+            // Must use ternary to select pre-constructed boolean values
+            result = val ? nlohmann::json(true) : nlohmann::json(false);
           }
         else
           {