diff --git a/ChangeLog b/ChangeLog
index cbe62ee88d..eb51a31bc7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -39,6 +39,9 @@
 	ifname is too long.
 	* hurd/hurdsig.c (interrupted_reply_port_location): Use
 	DIAG_IGNORE_NEEDS_COMMENT to silence warning with GCC 6 and before.
+	* sysdeps/mach/hurd/i386/exc2signal.c (_hurd_exception2signal): Add
+	hidden def.
+	* mach/spin-lock.c (__mutex_unlock): Add hidden def.
 
 2018-04-03  Wilco Dijkstra  <wdijkstr@arm.com>
 
diff --git a/mach/spin-lock.c b/mach/spin-lock.c
index 888eb9d708..e5c730d7fb 100644
--- a/mach/spin-lock.c
+++ b/mach/spin-lock.c
@@ -12,4 +12,5 @@ weak_alias (__spin_unlock, spin_unlock);
 libc_hidden_def (__spin_try_lock);
 weak_alias (__spin_try_lock, spin_try_lock);
 libc_hidden_def (__mutex_lock);
+libc_hidden_def (__mutex_unlock);
 libc_hidden_def (__mutex_trylock);
diff --git a/sysdeps/mach/hurd/i386/exc2signal.c b/sysdeps/mach/hurd/i386/exc2signal.c
index a7e2025ccb..57bc05df99 100644
--- a/sysdeps/mach/hurd/i386/exc2signal.c
+++ b/sysdeps/mach/hurd/i386/exc2signal.c
@@ -163,3 +163,4 @@ _hurd_exception2signal (struct hurd_signal_detail *detail, int *signo)
       break;
     }
 }
+libc_hidden_def (_hurd_exception2signal)