--- a/auto/unix
+++ b/auto/unix
@@ -450,6 +450,29 @@ Currently file AIO is supported on FreeB
 END
         exit 1
     fi
+
+else
+
+    ngx_feature="eventfd()"
+    ngx_feature_name="NGX_HAVE_EVENTFD"
+    ngx_feature_run=no
+    ngx_feature_incs="#include <sys/eventfd.h>"
+    ngx_feature_path=
+    ngx_feature_libs=
+    ngx_feature_test="(void) eventfd(0, 0)"
+    . auto/feature
+
+    if [ $ngx_found = yes ]; then
+        have=NGX_HAVE_SYS_EVENTFD_H . auto/have
+    fi
+
+    if [ $ngx_found = no ]; then
+
+        ngx_feature="eventfd() (SYS_eventfd)"
+        ngx_feature_incs="#include <sys/syscall.h>"
+        ngx_feature_test="int n = SYS_eventfd"
+        . auto/feature
+    fi
 fi