fixes warnings with -Wundef

re #470

changelog/current.md

@@ -29,6 +29,7 @@
 - [PR#485](https://github.com/biojppm/rapidyaml/pull/485): improve the CI workflows (thanks to @ingydotnet):
   - amazing code reuse and organization, thanks to the use of YamlScript to generate the final workflows
   - all optimization levels are now covered for gcc, clang and Visual Studio.
+- [PR#499](https://github.com/biojppm/rapidyaml/pull/499): fix warnings with `-Wundef`.
 
 
 ## Thanks

src/c4/yml/event_handler_tree.hpp

@@ -47,7 +47,7 @@ public:
     size_t m_num_directives;
     bool m_yaml_directive;
 
-    #if RYML_DBG
+    #ifdef RYML_DBG
     #define _enable_(bits) _enable__<bits>(); _c4dbgpf("node[{}]: enable {}", m_curr->node_id, #bits)
     #define _disable_(bits) _disable__<bits>(); _c4dbgpf("node[{}]: disable {}", m_curr->node_id, #bits)
     #else

test/test_suite/test_suite_common.hpp

@@ -16,7 +16,11 @@
 #include "test_lib/test_case.hpp"
 #include <gtest/gtest.h>
 
-#define RYML_NFO (0 || RYML_DBG)
+#if (0 || defined(RYML_DBG))
+#define RYML_NFO (1)
+#else
+#define RYML_NFO (0)
+#endif
 
 #if RYML_NFO
 #define _nfo_print_tree(title, tree) do { c4::log("{}:{}: " title ":", __FILE__, __LINE__); print_tree(tree); c4::yml::emit_yaml(tree, stdout); fflush(stdout); } while(0)