boot: Ensure raise() is not dropped by LTO

src/boot/efi/util.c

@@ -724,6 +724,6 @@ void *find_configuration_table(const EFI_GUID *guid) {
 
 /* libgcc's __aeabi_ldiv0 intrinsic will call raise() on division by zero, so we
  * need to provide one ourselves for now. */
-_noreturn_ int raise(int sig) {
+_used_ _noreturn_ int raise(int sig) {
         assert_not_reached();
 }