diff --git a/include/boost/config/compiler/clang.hpp b/include/boost/config/compiler/clang.hpp
index 47ea65b0..c78edb24 100644
--- a/include/boost/config/compiler/clang.hpp
+++ b/include/boost/config/compiler/clang.hpp
@@ -23,6 +23,10 @@
 #define __has_extension __has_feature
 #endif
 
+#ifndef __has_attribute
+#define __has_attribute(x) 0
+#endif
+
 #if !__has_feature(cxx_exceptions) && !defined(BOOST_NO_EXCEPTIONS)
 #  define BOOST_NO_EXCEPTIONS
 #endif
@@ -256,9 +260,7 @@
 #  define BOOST_NO_CXX14_DIGIT_SEPARATORS
 #endif
 
-
-// Unused attribute:
-#if defined(__GNUC__) && (__GNUC__ >= 4)
+#if __has_attribute(unused)
 #  define BOOST_ATTRIBUTE_UNUSED __attribute__((unused))
 #endif