diff --git a/lib/libc/gen/Makefile.inc b/lib/libc/gen/Makefile.inc
--- a/lib/libc/gen/Makefile.inc
+++ b/lib/libc/gen/Makefile.inc
@@ -9,6 +9,7 @@
 SRCS+= \
 	__pthread_mutex_init_calloc_cb_stub.c \
 	__xuname.c \
+	_once_stub.c \
 	_pthread_stubs.c \
 	_rand48.c \
 	_spinlock_stub.c \
@@ -46,7 +47,6 @@
 	erand48.c \
 	err.c \
 	errlst.c \
-	errno.c \
 	eventfd.c \
 	exec.c \
 	exect.c \
diff --git a/lib/libc/gen/Symbol.map b/lib/libc/gen/Symbol.map
--- a/lib/libc/gen/Symbol.map
+++ b/lib/libc/gen/Symbol.map
@@ -99,7 +99,6 @@
 	vwarnx;
 	sys_errlist;
 	sys_nerr;
-	errno;
 	exect;
 	execl;
 	execle;
diff --git a/lib/libsys/_once_stub.c b/lib/libc/gen/_once_stub.c
rename from lib/libsys/_once_stub.c
rename to lib/libc/gen/_once_stub.c
diff --git a/lib/libc/gen/errno.c b/lib/libc/gen/errno.c
deleted file mode 100644
--- a/lib/libc/gen/errno.c
+++ /dev/null
@@ -1,29 +0,0 @@
-/*-
- * SPDX-License-Identifier: BSD-2-Clause
- *
- * Copyright (c) 2002 Peter Wemm <peter@freebsd.org>
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-int errno;
diff --git a/lib/libsys/Makefile b/lib/libsys/Makefile
--- a/lib/libsys/Makefile
+++ b/lib/libsys/Makefile
@@ -21,11 +21,15 @@
 LIB=sys
 SHLIB_MAJOR= 7
 WARNS?=	2
+MK_SSP=		no
 
 CFLAGS+=-I${LIBSYS_SRCTOP}/include -I${LIBC_SRCTOP}/include
 CFLAGS+=-I${LIBSYS_SRCTOP}/${LIBC_ARCH}
 CFLAGS+=-I${LIBC_SRCTOP}/${LIBC_ARCH}
 
+.PATH: ${LIBC_SRCTOP}/string
+SRCS+=	memcpy.c memset.c strlcpy.c
+
 CLEANFILES+=tags
 INSTALL_PIC_ARCHIVE=
 #XXX? BUILD_NOSSP_PIC_ARCHIVE=
diff --git a/lib/libsys/Makefile.sys b/lib/libsys/Makefile.sys
--- a/lib/libsys/Makefile.sys
+++ b/lib/libsys/Makefile.sys
@@ -33,7 +33,6 @@
 SRCS+=	\
 	__error.c \
 	__getosreldate.c \
-	_once_stub.c \
 	getpagesize.c \
 	getpagesizes.c \
 	interposing_table.c
diff --git a/lib/libsys/Symbol.sys.map b/lib/libsys/Symbol.sys.map
--- a/lib/libsys/Symbol.sys.map
+++ b/lib/libsys/Symbol.sys.map
@@ -76,6 +76,7 @@
 	extattr_set_file;
 	extattr_set_link;
 	extattrctl;
+	errno;
 	fchdir;
 	fchflags;
 	fchmod;
diff --git a/lib/libsys/__error.c b/lib/libsys/__error.c
--- a/lib/libsys/__error.c
+++ b/lib/libsys/__error.c
@@ -31,7 +31,7 @@
 
 #include "libc_private.h"
 
-extern int errno;
+int errno;
 
 static int *
 __error_unthreaded(void)
diff --git a/lib/libsys/auxv.c b/lib/libsys/auxv.c
--- a/lib/libsys/auxv.c
+++ b/lib/libsys/auxv.c
@@ -31,6 +31,7 @@
 #include <errno.h>
 #include <link.h>
 #include <pthread.h>
+#include <stdbool.h>
 #include <string.h>
 #include <sys/auxv.h>
 #include "un-namespace.h"
@@ -40,6 +41,8 @@
 #pragma weak _DYNAMIC
 
 void *__elf_aux_vector;
+
+#ifndef PIC
 static pthread_once_t aux_vector_once = PTHREAD_ONCE_INIT;
 
 static void
@@ -61,8 +64,9 @@
 		return;
 	_once(&aux_vector_once, init_aux_vector_once);
 }
+#endif
 
-static pthread_once_t aux_once = PTHREAD_ONCE_INIT;
+static bool aux_once = false;
 static int pagesize, osreldate, canary_len, ncpus, pagesizes_len, bsdflags;
 static int hwcap_present, hwcap2_present;
 static char *canary, *pagesizes, *execpath;
@@ -77,11 +81,19 @@
 int _powerpc_elf_aux_info(int, void *, int);
 #endif
 
+/*
+ * This function might be called and actual body executed more than
+ * once in multithreading environment.  Due to this, it is and must
+ * continue to be idempotent.  All stores are atomic (no store
+ * tearing), because we only assign to int/long/ptr.
+ */
 static void
 init_aux(void)
 {
 	Elf_Auxinfo *aux;
 
+	if (aux_once)
+		return;
 	for (aux = __elf_aux_vector; aux->a_type != AT_NULL; aux++) {
 		switch (aux->a_type) {
 		case AT_BSDFLAGS:
@@ -166,6 +178,8 @@
 	if (!powerpc_new_auxv_format)
 		_init_aux_powerpc_fixup();
 #endif
+
+	aux_once = true;
 }
 
 #ifdef __powerpc__
@@ -256,10 +270,12 @@
 {
 	int res;
 
+#ifndef PIC
 	__init_elf_aux_vector();
+#endif
 	if (__elf_aux_vector == NULL)
 		return (ENOSYS);
-	_once(&aux_once, init_aux);
+	init_aux();	/* idempotent */
 
 	if (buflen < 0)
 		return (EINVAL);
diff --git a/libexec/rtld-elf/rtld-libc/rtld_libc.c b/libexec/rtld-elf/rtld-libc/rtld_libc.c
--- a/libexec/rtld-elf/rtld-libc/rtld_libc.c
+++ b/libexec/rtld-elf/rtld-libc/rtld_libc.c
@@ -105,7 +105,7 @@
 	return (page_size);
 }
 
-extern int __sys___sysctl(const int *name, u_int namelen, void *oldp,
+int __sys___sysctl(const int *name, u_int namelen, void *oldp,
     size_t *oldlenp, const void *newp, size_t newlen);
 
 int