Initial plan

tinyxml2.cpp

@@ -36,10 +36,17 @@ distribution.
 #ifndef __has_attribute
 #   define __has_attribute(x) 0
 #endif
+#ifdef __cplusplus
 #   ifndef __has_cpp_attribute
 #      define __has_cpp_attribute(x) 0
 #   endif
+#else
+#   ifndef __has_c_attribute
+#      define __has_c_attribute(x) 0
+#   endif
+#endif
 
+#ifdef __cplusplus
 #   if defined(_MSC_VER)
 #      define TIXML_FALLTHROUGH (void(0))
 #   elif (__cplusplus >= 201703L && __has_cpp_attribute(fallthrough))
@@ -51,6 +58,17 @@ distribution.
 #   else
 #      define TIXML_FALLTHROUGH (void(0))
 #   endif
+#else
+#   if defined(_MSC_VER)
+#      define TIXML_FALLTHROUGH (void(0))
+#   elif __has_c_attribute(fallthrough)
+#      define TIXML_FALLTHROUGH [[fallthrough]]
+#   elif __has_attribute(fallthrough)
+#      define TIXML_FALLTHROUGH __attribute__((fallthrough))
+#   else
+#      define TIXML_FALLTHROUGH (void(0))
+#   endif
+#endif
 
 
 #if defined(_MSC_VER) && (_MSC_VER >= 1400 ) && (!defined WINCE)