diff --git a/libgcc/gthr-posix.h b/libgcc/gthr-posix.h
index f1a5ab8e075c4..90fe01d16b40f 100644
--- a/libgcc/gthr-posix.h
+++ b/libgcc/gthr-posix.h
@@ -44,6 +44,63 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 # endif
 #endif
 
+#define PTHREAD_MUTEX_INITIALIZER (-1)
+#define PTHREAD_MUTEX_NORMAL        0
+#define PTHREAD_MUTEX_RECURSIVE     1
+#define PTHREAD_MUTEX_ERRORCHECK    2
+#define PTHREAD_MUTEX_DEFAULT       PTHREAD_MUTEX_NORMAL
+
+#define PTHREAD_COND_INITIALIZER (-1)
+
+#define PTHREAD_ONCE_INIT {1,0}
+
+/* https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_cancel.html */
+int pthread_cancel(pthread_t thread);
+/* https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_cond_broadcast.html */
+int pthread_cond_broadcast(pthread_cond_t *cond);
+/* https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_cond_destroy.html */
+int pthread_cond_destroy(pthread_cond_t *cond);
+int pthread_cond_init(pthread_cond_t *cond, const pthread_condattr_t *__restrict attr);
+/* https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_cond_broadcast.html */
+int pthread_cond_signal(pthread_cond_t *cond);
+/* https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_cond_timedwait.html */
+int pthread_cond_timedwait(pthread_cond_t *__restrict cond, pthread_mutex_t *__restrict mutex, const struct timespec *__restrict abstime);
+int pthread_cond_wait(pthread_cond_t *__restrict cond, pthread_mutex_t *__restrict mutex);
+/* https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_create.html */
+int pthread_create(pthread_t *__restrict thread, const pthread_attr_t *__restrict attr, void *(*start_routine)(void*), void *__restrict arg);
+/* https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_detach.html */
+int pthread_detach(pthread_t thread);
+/* https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_equal.html */
+int pthread_equal(pthread_t t1, pthread_t t2);
+/* https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_getspecific.html */
+void *pthread_getspecific(pthread_key_t key);
+/* https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_join.html */
+int pthread_join(pthread_t thread, void **value_ptr);
+/* https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_key_create.html */
+int pthread_key_create(pthread_key_t *key, void (*destructor)(void*));
+/* https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_key_delete.html */
+int pthread_key_delete(pthread_key_t key);
+/* https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_mutexattr_destroy.html */
+int pthread_mutexattr_destroy(pthread_mutexattr_t *attr);
+int pthread_mutexattr_init(pthread_mutexattr_t *attr);
+/* https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_mutexattr_gettype.html */
+int pthread_mutexattr_settype(pthread_mutexattr_t *attr, int type);
+/* https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_mutex_destroy.html */
+int pthread_mutex_destroy(pthread_mutex_t *mutex);
+int pthread_mutex_init(pthread_mutex_t *__restrict mutex, const pthread_mutexattr_t *__restrict attr);
+/* https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_mutex_lock.html */
+int pthread_mutex_lock(pthread_mutex_t *mutex);
+int pthread_mutex_trylock(pthread_mutex_t *mutex);
+int pthread_mutex_unlock(pthread_mutex_t *mutex);
+/* https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_once.html */
+int pthread_once(pthread_once_t *once_control, void (*init_routine)(void));
+/* https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/pthread.h.html */
+pthread_t pthread_self(void);
+/* https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_getspecific.html */
+int pthread_setspecific(pthread_key_t key, const void *value);
+/* https://pubs.opengroup.org/onlinepubs/9699919799/functions/sched_yield.html */
+int sched_yield(void);
+
 typedef pthread_t __gthread_t;
 typedef pthread_key_t __gthread_key_t;
 typedef pthread_once_t __gthread_once_t;