diff --git a/build-aux/config.guess b/build-aux/config.guess
index e94095c5..8d70ec2b 100644
--- a/build-aux/config.guess
+++ b/build-aux/config.guess
@@ -2,7 +2,7 @@
 # Attempt to guess a canonical system name.
 #   Copyright 1992-2020 Free Software Foundation, Inc.
 
-timestamp='2020-07-12'
+timestamp='2020-09-19'
 
 # This file is free software; you can redistribute it and/or modify it
 # under the terms of the GNU General Public License as published by
@@ -150,17 +150,15 @@ Linux|GNU|GNU/*)
 	#elif defined(__dietlibc__)
 	LIBC=dietlibc
 	#else
+	#include <stdarg.h>
+	#ifdef __DEFINED_va_list
+	LIBC=musl
+	#else
 	LIBC=gnu
 	#endif
+	#endif
 	EOF
 	eval "`$CC_FOR_BUILD -E "$dummy.c" 2>/dev/null | grep '^LIBC' | sed 's, ,,g'`"
-
-	# If ldd exists, use it to detect musl libc.
-	if command -v ldd >/dev/null && \
-		ldd --version 2>&1 | grep -q ^musl
-	then
-	    LIBC=musl
-	fi
 	;;
 esac
 
@@ -404,7 +402,7 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
 	# If there is a compiler, see if it is configured for 64-bit objects.
 	# Note that the Sun cc does not turn __LP64__ into 1 like gcc does.
 	# This test works for both compilers.
-	if [ "$CC_FOR_BUILD" != no_compiler_found ]; then
+	if test "$CC_FOR_BUILD" != no_compiler_found; then
 	    if (echo '#ifdef __amd64'; echo IS_64BIT_ARCH; echo '#endif') | \
 		(CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
 		grep IS_64BIT_ARCH >/dev/null
@@ -544,10 +542,10 @@ EOF
     AViiON:dgux:*:*)
 	# DG/UX returns AViiON for all architectures
 	UNAME_PROCESSOR=`/usr/bin/uname -p`
-	if [ "$UNAME_PROCESSOR" = mc88100 ] || [ "$UNAME_PROCESSOR" = mc88110 ]
+	if test "$UNAME_PROCESSOR" = mc88100 || test "$UNAME_PROCESSOR" = mc88110
 	then
-	    if [ "$TARGET_BINARY_INTERFACE"x = m88kdguxelfx ] || \
-	       [ "$TARGET_BINARY_INTERFACE"x = x ]
+	    if test "$TARGET_BINARY_INTERFACE"x = m88kdguxelfx || \
+	       test "$TARGET_BINARY_INTERFACE"x = x
 	    then
 		echo m88k-dg-dgux"$UNAME_RELEASE"
 	    else
@@ -580,7 +578,7 @@ EOF
 	echo i386-ibm-aix
 	exit ;;
     ia64:AIX:*:*)
-	if [ -x /usr/bin/oslevel ] ; then
+	if test -x /usr/bin/oslevel ; then
 		IBM_REV=`/usr/bin/oslevel`
 	else
 		IBM_REV="$UNAME_VERSION.$UNAME_RELEASE"
@@ -620,7 +618,7 @@ EOF
 	else
 		IBM_ARCH=powerpc
 	fi
-	if [ -x /usr/bin/lslpp ] ; then
+	if test -x /usr/bin/lslpp ; then
 		IBM_REV=`/usr/bin/lslpp -Lqc bos.rte.libc |
 			   awk -F: '{ print $3 }' | sed s/[0-9]*$/0/`
 	else
@@ -655,7 +653,7 @@ EOF
 	    9000/31?)            HP_ARCH=m68000 ;;
 	    9000/[34]??)         HP_ARCH=m68k ;;
 	    9000/[678][0-9][0-9])
-		if [ -x /usr/bin/getconf ]; then
+		if test -x /usr/bin/getconf; then
 		    sc_cpu_version=`/usr/bin/getconf SC_CPU_VERSION 2>/dev/null`
 		    sc_kernel_bits=`/usr/bin/getconf SC_KERNEL_BITS 2>/dev/null`
 		    case "$sc_cpu_version" in
@@ -669,7 +667,7 @@ EOF
 			esac ;;
 		    esac
 		fi
-		if [ "$HP_ARCH" = "" ]; then
+		if test "$HP_ARCH" = ""; then
 		    set_cc_for_build
 		    sed 's/^		//' << EOF > "$dummy.c"
 
@@ -708,7 +706,7 @@ EOF
 		    test -z "$HP_ARCH" && HP_ARCH=hppa
 		fi ;;
 	esac
-	if [ "$HP_ARCH" = hppa2.0w ]
+	if test "$HP_ARCH" = hppa2.0w
 	then
 	    set_cc_for_build
 
@@ -782,7 +780,7 @@ EOF
 	echo hppa1.0-hp-osf
 	exit ;;
     i*86:OSF1:*:*)
-	if [ -x /usr/sbin/sysversion ] ; then
+	if test -x /usr/sbin/sysversion ; then
 	    echo "$UNAME_MACHINE"-unknown-osf1mk
 	else
 	    echo "$UNAME_MACHINE"-unknown-osf1
@@ -1097,7 +1095,7 @@ EOF
     x86_64:Linux:*:*)
 	set_cc_for_build
 	LIBCABI=$LIBC
-	if [ "$CC_FOR_BUILD" != no_compiler_found ]; then
+	if test "$CC_FOR_BUILD" != no_compiler_found; then
 	    if (echo '#ifdef __ILP32__'; echo IS_X32; echo '#endif') | \
 		(CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
 		grep IS_X32 >/dev/null
@@ -1294,7 +1292,7 @@ EOF
 	echo mips-sony-newsos6
 	exit ;;
     R[34]000:*System_V*:*:* | R4000:UNIX_SYSV:*:* | R*000:UNIX_SV:*:*)
-	if [ -d /usr/nec ]; then
+	if test -d /usr/nec; then
 		echo mips-nec-sysv"$UNAME_RELEASE"
 	else
 		echo mips-unknown-sysv"$UNAME_RELEASE"
@@ -1359,7 +1357,7 @@ EOF
 	else
 	    set_cc_for_build
 	fi
-	if [ "$CC_FOR_BUILD" != no_compiler_found ]; then
+	if test "$CC_FOR_BUILD" != no_compiler_found; then
 	    if (echo '#ifdef __LP64__'; echo IS_64BIT_ARCH; echo '#endif') | \
 		   (CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
 		   grep IS_64BIT_ARCH >/dev/null
diff --git a/build-aux/config.sub b/build-aux/config.sub
index 3d9a8dc3..780c2bba 100644
--- a/build-aux/config.sub
+++ b/build-aux/config.sub
@@ -2,7 +2,7 @@
 # Configuration validation subroutine script.
 #   Copyright 1992-2020 Free Software Foundation, Inc.
 
-timestamp='2020-07-10'
+timestamp='2020-09-08'
 
 # This file is free software; you can redistribute it and/or modify it
 # under the terms of the GNU General Public License as published by
@@ -1278,7 +1278,7 @@ esac
 
 # Decode manufacturer-specific aliases for certain operating systems.
 
-if [ x$basic_os != x ]
+if test x$basic_os != x
 then
 
 # First recognize some ad-hoc caes, or perhaps split kernel-os, or else just
@@ -1367,13 +1367,7 @@ case $os in
 		os=psos
 		;;
 	qnx*)
-		case $cpu in
-		    x86 | i*86)
-			;;
-		    *)
-			os=nto-$os
-			;;
-		esac
+		os=qnx
 		;;
 	hiux*)
 		os=hiuxwe2
@@ -1722,7 +1716,7 @@ case $os in
 	     | skyos* | haiku* | rdos* | toppers* | drops* | es* \
 	     | onefs* | tirtos* | phoenix* | fuchsia* | redox* | bme* \
 	     | midnightbsd* | amdhsa* | unleashed* | emscripten* | wasi* \
-	     | nsk* | powerunix* | genode* | zvmoe* )
+	     | nsk* | powerunix* | genode* | zvmoe* | qnx* )
 		;;
 	# This one is extra strict with allowed versions
 	sco3.2v2 | sco3.2v[4-9]* | sco5v6*)