diff --git a/libcxx/include/format b/libcxx/include/format
--- a/libcxx/include/format
+++ b/libcxx/include/format
@@ -55,14 +55,14 @@
 
 */
 
+// Make sure all feature tests macros are always available.
+#include <version>
+// Only enable the contents of the header when libc++ was build with LIBCXX_ENABLE_INCOMPLETE_FEATURES enabled
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
+
 #include <__config>
 #include <__format/format_error.h>
 #include <__format/format_parse_context.h>
-#include <version>
-
-#if defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
-# error "The Format library is not supported since libc++ has been configured with LIBCXX_ENABLE_INCOMPLETE_FEATURES disabled"
-#endif
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -81,4 +81,6 @@
 
 _LIBCPP_POP_MACROS
 
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
+
 #endif // _LIBCPP_FORMAT
diff --git a/libcxx/include/ranges b/libcxx/include/ranges
--- a/libcxx/include/ranges
+++ b/libcxx/include/ranges
@@ -170,6 +170,11 @@
 
 */
 
+// Make sure all feature tests macros are always available.
+#include <version>
+// Only enable the contents of the header when libc++ was build with LIBCXX_ENABLE_INCOMPLETE_FEATURES enabled
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
+
 #include <__config>
 #include <__ranges/access.h>
 #include <__ranges/all.h>
@@ -193,11 +198,6 @@
 #include <initializer_list> // Required by the standard.
 #include <iterator>         // Required by the standard.
 #include <type_traits>
-#include <version>
-
-#if defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
-# error "The Ranges library is not supported since libc++ has been configured with LIBCXX_ENABLE_INCOMPLETE_FEATURES disabled"
-#endif
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
@@ -216,4 +216,6 @@
 
 _LIBCPP_POP_MACROS
 
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
+
 #endif // _LIBCPP_RANGES