diff --git a/src/env_universal_common.cpp b/src/env_universal_common.cpp
index d509b5f3f..d25d79737 100644
--- a/src/env_universal_common.cpp
+++ b/src/env_universal_common.cpp
@@ -1574,7 +1574,8 @@ class universal_notifier_named_pipe_t final : public universal_notifier_t {
 universal_notifier_t::notifier_strategy_t universal_notifier_t::resolve_default_strategy() {
 #ifdef FISH_NOTIFYD_AVAILABLE
     return strategy_notifyd;
-#elif defined(SIGIO)
+    // Note: We use POLL_IN to query SIGIO information, without it it is useless.
+#elif defined(SIGIO) && defined(POLL_IN)
     return strategy_sigio;
 #elif defined(__CYGWIN__)
     return strategy_shmem_polling;
diff --git a/src/signal.cpp b/src/signal.cpp
index f3640fba3..6abfde6ed 100644
--- a/src/signal.cpp
+++ b/src/signal.cpp
@@ -276,6 +276,7 @@ static void fish_signal_handler(int sig, siginfo_t *info, void *context) {
             // test, to verify that we behave correctly when receiving lots of irrelevant signals.
             break;
 
+#if defined(SIGIO) && defined(POLL_IN)
         case SIGIO:
             // An async FD became readable/writable/etc.
             if (info->si_code == POLL_IN) {
@@ -283,6 +284,7 @@ static void fish_signal_handler(int sig, siginfo_t *info, void *context) {
                 s_signal_pollin_count = s_signal_pollin_count + 1;
             }
             break;
+#endif
     }
     errno = saved_errno;
 }