diff --git a/ChangeLog b/ChangeLog
index 616e3705e1..998f4c153f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2018-12-05  Samuel Thibault  <samuel.thibault@ens-lyon.org>
+
+	* include/unistd.h (__confstr): Add prototype and hidden prototype.
+	* posix/confstr.c (confstr): Rename to __confstr.
+	(__confstr): Add hidden def.
+	(confstr): Add weak alias for __confstr.
+	* sysdeps/mach/hurd/spawni.c (__spawni): Call __confstr instead of
+	confstr.
+
 2018-12-07  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* NEWS: Mention getcpu.
diff --git a/include/unistd.h b/include/unistd.h
index a171b00326..a043431ecf 100644
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -6,6 +6,8 @@
 libc_hidden_proto (_exit, __noreturn__)
 rtld_hidden_proto (_exit, __noreturn__)
 libc_hidden_proto (alarm)
+extern size_t __confstr (int name, char *buf, size_t len);
+libc_hidden_proto (__confstr)
 libc_hidden_proto (confstr)
 libc_hidden_proto (execl)
 libc_hidden_proto (execle)
diff --git a/posix/confstr.c b/posix/confstr.c
index de4cff76cc..73ebb2e254 100644
--- a/posix/confstr.c
+++ b/posix/confstr.c
@@ -29,7 +29,7 @@
    of BUF with the value corresponding to NAME and zero-terminate BUF.
    Return the number of bytes required to hold NAME's entire value.  */
 size_t
-confstr (int name, char *buf, size_t len)
+__confstr (int name, char *buf, size_t len)
 {
   const char *string = "";
   size_t string_len = 1;
@@ -289,4 +289,6 @@ confstr (int name, char *buf, size_t len)
     }
   return string_len;
 }
+libc_hidden_def (__confstr)
 libc_hidden_def (confstr)
+weak_alias (__confstr, confstr)
diff --git a/sysdeps/mach/hurd/spawni.c b/sysdeps/mach/hurd/spawni.c
index 16c927be24..e31b21ceea 100644
--- a/sysdeps/mach/hurd/spawni.c
+++ b/sysdeps/mach/hurd/spawni.c
@@ -673,10 +673,10 @@ __spawni (pid_t *pid, const char *file,
 	  /* There is no `PATH' in the environment.
 	     The default search path is the current directory
 	     followed by the path `confstr' returns for `_CS_PATH'.  */
-	  len = confstr (_CS_PATH, (char *) NULL, 0);
+	  len = __confstr (_CS_PATH, (char *) NULL, 0);
 	  path = (char *) __alloca (1 + len);
 	  path[0] = ':';
-	  (void) confstr (_CS_PATH, path + 1, len);
+	  (void) __confstr (_CS_PATH, path + 1, len);
 	}
 
       len = strlen (file) + 1;