diff --git a/src/ChangeLog b/src/ChangeLog
index 64e41ce3..855a59ba 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,9 @@
+2005-04-29  Hrvoje Niksic  <hniksic@xemacs.org>
+
+	* ptimer.c (posix_init): Since we allow _POSIX_MONOTONIC_CLOCK==0,
+	it is not enough to check for _POSIX_MONOTONIC_CLOCK-0, we must
+	also check for defined(_POSIX_MONOTONIC_CLOCK).
+
 2005-04-28  Hrvoje Niksic  <hniksic@xemacs.org>
 
 	* ftp.c, hash.c, connect.c, host.c, http.c: Remove unreached code,
diff --git a/src/ptimer.c b/src/ptimer.c
index 3eeb78c6..52b8111e 100644
--- a/src/ptimer.c
+++ b/src/ptimer.c
@@ -139,7 +139,7 @@ posix_init (void)
     int id;
     int sysconf_name;
   } clocks[] = {
-#if _POSIX_MONOTONIC_CLOCK - 0 >= 0
+#if defined(_POSIX_MONOTONIC_CLOCK) && _POSIX_MONOTONIC_CLOCK - 0 >= 0
     { CLOCK_MONOTONIC, _SC_MONOTONIC_CLOCK },
 #endif
 #ifdef CLOCK_HIGHRES