diff --git a/ChangeLog b/ChangeLog
index 2d813a8eef..c853b65493 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2018-04-02  Samuel Thibault  <samuel.thibault@ens-lyon.org>
+
+	* sysdeps/mach/hurd/bits/local_lim.h (_POSIX_THREAD_KEYS_MAX,
+	_POSIX_THREAD_DESTRUCTOR_ITERATIONS, _POSIX_THREAD_THREADS_MAX): Define
+	macros.
+	* sysdeps/mach/hurd/bits/posix_opt.h (_POSIX_THREADS,
+	_POSIX_THREAD_ATTR_STACKSIZE, _POSIX_THREAD_ATTR_STACKADDR,
+	_POSIX_SEMAPHORES, _POSIX_READER_WRITER_LOCKS, _POSIX_TIMEOUTS,
+	_POSIX_SPIN_LOCKS, _POSIX_BARRIERS): Define macros to 200809L.
+
 2018-04-02  Agustina Arzille  <avarzille@riseup.net>
             Amos Jeffries  <squid3@treenet.co.nz>
             David Michael  <fedora.dm0@gmail.com>
diff --git a/sysdeps/mach/hurd/bits/local_lim.h b/sysdeps/mach/hurd/bits/local_lim.h
index 8a1af914f3..97f87ad5d2 100644
--- a/sysdeps/mach/hurd/bits/local_lim.h
+++ b/sysdeps/mach/hurd/bits/local_lim.h
@@ -32,3 +32,12 @@
    suitable, and `sysconf' will return a number at least as large.  */
 
 #define NGROUPS_MAX	256
+
+/* The number of data keys per process.  */
+#define _POSIX_THREAD_KEYS_MAX	128
+
+/* Controlling the iterations of destructors for thread-specific data.  */
+#define _POSIX_THREAD_DESTRUCTOR_ITERATIONS	4
+
+/* The number of threads per process.  */
+#define _POSIX_THREAD_THREADS_MAX	64
diff --git a/sysdeps/mach/hurd/bits/posix_opt.h b/sysdeps/mach/hurd/bits/posix_opt.h
index d42c010c20..dfb0ba46ec 100644
--- a/sysdeps/mach/hurd/bits/posix_opt.h
+++ b/sysdeps/mach/hurd/bits/posix_opt.h
@@ -71,24 +71,38 @@
 /* XPG4.2 shared memory is not supported.  */
 #undef	_XOPEN_SHM
 
-/* We do not have the POSIX threads interface.  */
-#define _POSIX_THREADS	-1
+/* Tell we have POSIX threads.  */
+#define _POSIX_THREADS	200809L
 
 /* We have the reentrant functions described in POSIX.  */
 #define _POSIX_REENTRANT_FUNCTIONS      1
 #define _POSIX_THREAD_SAFE_FUNCTIONS	200809L
 
-/* These are all things that won't be supported when _POSIX_THREADS is not.  */
+/* We do not provide priority scheduling for threads.  */
 #define _POSIX_THREAD_PRIORITY_SCHEDULING	-1
-#define _POSIX_THREAD_ATTR_STACKSIZE		-1
-#define _POSIX_THREAD_ATTR_STACKADDR		-1
+
+/* We support user-defined stack sizes.  */
+#define _POSIX_THREAD_ATTR_STACKSIZE	200809L
+
+/* We support user-defined stacks.  */
+#define _POSIX_THREAD_ATTR_STACKADDR	200809L
+
+/* We do not support priority inheritence.  */
 #define _POSIX_THREAD_PRIO_INHERIT		-1
+
+/* We do not support priority protection.  */
 #define _POSIX_THREAD_PRIO_PROTECT		-1
+
 #ifdef __USE_XOPEN2K8
+/* We do not support priority inheritence for robust mutexes.  */
 # define _POSIX_THREAD_ROBUST_PRIO_INHERIT	-1
+
+/* We do not support priority protection for robust mutexes.  */
 # define _POSIX_THREAD_ROBUST_PRIO_PROTECT	-1
 #endif
-#define _POSIX_SEMAPHORES			-1
+
+/* We support POSIX.1b semaphores.  */
+#define _POSIX_SEMAPHORES			200809L
 
 /* Real-time signals are not yet supported.  */
 #define _POSIX_REALTIME_SIGNALS	-1
@@ -121,17 +135,17 @@
 /* GNU libc provides regular expression handling.  */
 #define _POSIX_REGEXP	1
 
-/* Reader/Writer locks are not available.  */
-#define _POSIX_READER_WRITER_LOCKS	-1
+/* Reader/Writer locks are available.  */
+#define _POSIX_READER_WRITER_LOCKS	200809L
 
 /* We have a POSIX shell.  */
 #define _POSIX_SHELL	1
 
-/* We cannot support the Timeouts option without _POSIX_THREADS.  */
-#define _POSIX_TIMEOUTS	-1
+/* We support the Timeouts option.  */
+#define _POSIX_TIMEOUTS	200809L
 
-/* We do not support spinlocks.  */
-#define _POSIX_SPIN_LOCKS	-1
+/* We support spinlocks.  */
+#define _POSIX_SPIN_LOCKS	200809L
 
 /* The `spawn' function family is supported.  */
 #define _POSIX_SPAWN	200809L
@@ -139,8 +153,8 @@
 /* We do not have POSIX timers, but could in future without ABI change.  */
 #define _POSIX_TIMERS	0
 
-/* The barrier functions are not available.  */
-#define _POSIX_BARRIERS	-1
+/* The barrier functions are available.  */
+#define _POSIX_BARRIERS	200809L
 
 /* POSIX message queues could be available in future.  */
 #define	_POSIX_MESSAGE_PASSING	0