diff --git a/kdm/backend/dm.h b/kdm/backend/dm.h
index 8a9e817c..61e27ea6 100644
--- a/kdm/backend/dm.h
+++ b/kdm/backend/dm.h
@@ -65,11 +65,7 @@ extern char **environ;
 #endif
 
 #ifndef PATH_MAX
-# ifdef MAXPATHLEN
-#  define PATH_MAX MAXPATHLEN
-# else
-#  define PATH_MAX 1024
-# endif
+# define PATH_MAX _POSIX_PATH_MAX
 #endif
 
 #include <sys/wait.h>
diff --git a/kioslave/nfs/nfsv3.cpp b/kioslave/nfs/nfsv3.cpp
index 562d7a97..43ce2ab1 100644
--- a/kioslave/nfs/nfsv3.cpp
+++ b/kioslave/nfs/nfsv3.cpp
@@ -55,10 +55,13 @@
 
 #include "nfsv3.h"
 
+#ifndef PATH_MAX
+# define PATH_MAX _POSIX_PATH_MAX
+#endif
+
 // This ioslave is for NFS version 3.
 #define NFSPROG 100003UL
 #define NFSVERS 3UL
-
 #define NFS3_MAXDATA    32768
 #define NFS3_MAXPATHLEN PATH_MAX