diff --git a/libs/apr/include/apr.h.in b/libs/apr/include/apr.h.in
index 04b0d2d2a6..1a3e69637b 100644
--- a/libs/apr/include/apr.h.in
+++ b/libs/apr/include/apr.h.in
@@ -385,6 +385,8 @@ typedef  @socklen_t_value@       apr_socklen_t;
 #define APR_PATH_MAX       PATH_MAX
 #elif defined(_POSIX_PATH_MAX)
 #define APR_PATH_MAX       _POSIX_PATH_MAX
+#elif defined(_XOPEN_PATH_MAX)
+#define APR_PATH_MAX       _XOPEN_PATH_MAX
 #else
 #error no decision has been made on APR_PATH_MAX for your platform
 #endif