gentoo-overlay/sys-auth/elogind/files/elogind-246.10-clang-undefined-symbol.patch

--- a/src/libelogind/sd-bus/bus-error.h
+++ b/src/libelogind/sd-bus/bus-error.h
@@ -28,11 +28,17 @@ int bus_error_set_errnofv(sd_bus_error *e, int error, const char *format, va_lis
  * the bus error table, and BUS_ERROR_MAP_ELF_USE has to be used at
  * least once per compilation unit (i.e. per library), to ensure that
  * the error map is really added to the final binary.
+ *
+ * In addition, set the retain attribute so that the section cannot be
+ * discarded by ld --gc-sections -z start-stop-gc. Older compilers would
+ * warn for the unknown attribute, so just disable -Wattributes.
  */
 
 #define BUS_ERROR_MAP_ELF_REGISTER                                      \
+        _Pragma("GCC diagnostic ignored \"-Wattributes\"")              \
         _section_("SYSTEMD_BUS_ERROR_MAP")                              \
         _used_                                                          \
+        __attribute__((retain))                                         \
         _alignptr_                                                      \
         _variable_no_sanitize_address_