diff --git a/src/system_error.cpp b/src/system_error.cpp
index 3a22554..4ecafea 100644
--- a/src/system_error.cpp
+++ b/src/system_error.cpp
@@ -29,9 +29,11 @@
 
 // class error_category
 
+#if defined(_LIBCPP_DEPRECATED_ABI_EXTERNAL_ERROR_CATEGORY_CONSTRUCTOR)
 error_category::error_category() _NOEXCEPT
 {
 }
+#endif
 
 error_category::~error_category() _NOEXCEPT
 {