diff --git a/src/setup/language.cpp b/src/setup/language.cpp
index b6b70db..6b40813 100644
--- a/src/setup/language.cpp
+++ b/src/setup/language.cpp
@@ -44,7 +44,7 @@ bool operator<(windows_language language, boost::uint32_t language_id) {
 	return language.language_id < language_id;
 }
 
-#if defined(__clang_major__) && __clang_major__ < 8
+#if defined(__clang_major__) && __clang_major__ < 8 && defined(_LIBCPP_DEBUG)
 // Required for debug builds with Clang < 8
 bool operator<(boost::uint32_t language_id, windows_language language) {
 	return language_id < language.language_id;