diff --git a/include/haproxy/compiler.h b/include/haproxy/compiler.h
index 3e0049376..86d4ddf5a 100644
--- a/include/haproxy/compiler.h
+++ b/include/haproxy/compiler.h
@@ -90,6 +90,25 @@
 #define __attribute__(x) __attribute__(x)
 #endif
 
+/* attribute(warning) was added in gcc 4.3 */
+#if defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3))
+#  define __has_attribute_warning 1
+#endif
+
+/* __attribute__warning(x) does __attribute__((warning(x))) if supported by the
+ * compiler, otherwise __attribute__((deprecated)). Clang supports it since v14
+ * but is a bit capricious in that it refuses a redefinition with a warning
+ * attribute that wasn't there the first time. However it's OK with deprecated(x)
+ * so better use this one. See: https://github.com/llvm/llvm-project/issues/56519
+ */
+#if defined(__clang__)
+#  define __attribute__warning(x) __attribute__((deprecated(x)))
+#elif __has_attribute(warning)
+#  define __attribute__warning(x) __attribute__((warning(x)))
+#else
+#  define __attribute__warning(x) __attribute__((deprecated))
+#endif
+
 /* By default, gcc does not inline large chunks of code, but we want it to
  * respect our choices.
  */