diff --git a/stdlib/tst-realpath-toolong.c b/stdlib/tst-realpath-toolong.c
index 8bed772460..4388890294 100644
--- a/stdlib/tst-realpath-toolong.c
+++ b/stdlib/tst-realpath-toolong.c
@@ -29,6 +29,10 @@
 
 #define BASENAME "tst-realpath-toolong."
 
+#ifndef PATH_MAX
+# define PATH_MAX 1024
+#endif
+
 int
 do_test (void)
 {