diff --git a/ext/pty/extconf.rb b/ext/pty/extconf.rb
index 7721a744c8..038bdf4d2c 100644
--- a/ext/pty/extconf.rb
+++ b/ext/pty/extconf.rb
@@ -10,9 +10,9 @@ if /mswin|mingw|bccwin/ !~ RUBY_PLATFORM
   have_header("util.h") # OpenBSD openpty
   have_header("pty.h")
   have_header("pwd.h")
-  have_library("util", "openpty")
+  util = have_library("util", "openpty")
   if have_func("posix_openpt") or
-      have_func("openpty") or
+      (util or have_func("openpty")) or
       have_func("_getpty") or
       have_func("ptsname") or
       have_func("ioctl")