Sync with upstream

3 files changed, 241 insertions, 335 deletions

diff --git a/mk/gnu-config/config.guess b/mk/gnu-config/config.guess
index bbd48b60e88..31e01efec3e 100755
--- a/mk/gnu-config/config.guess
+++ b/mk/gnu-config/config.guess
@@ -2,7 +2,7 @@
 # Attempt to guess a canonical system name.
 #   Copyright 1992-2017 Free Software Foundation, Inc.
 
-timestamp='2017-01-01'
+timestamp='2017-11-07'
 
 # 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
@@ -15,7 +15,7 @@ timestamp='2017-01-01'
 # General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
-# along with this program; if not, see <http://www.gnu.org/licenses/>.
+# along with this program; if not, see <https://www.gnu.org/licenses/>.
 #
 # As a special exception to the GNU General Public License, if you
 # distribute this file as part of a program that contains a
@@ -27,7 +27,7 @@ timestamp='2017-01-01'
 # Originally written by Per Bothner; maintained since 2000 by Ben Elliston.
 #
 # You can get the latest version of this script from:
-# http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.guess
+# https://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.guess
 #
 # Please send patches to <config-patches@gnu.org>.
 
@@ -39,7 +39,7 @@ Usage: $0 [OPTION]
 
 Output the configuration name of the system \`$me' is run on.
 
-Operation modes:
+Options:
   -h, --help         print this help, then exit
   -t, --time-stamp   print date of last modification, then exit
   -v, --version      print version number, then exit
@@ -244,6 +244,9 @@ case "${UNAME_MACHINE}:${UNAME_SYSTEM}:${UNAME_RELEASE}:${UNAME_VERSION}" in
 	UNAME_MACHINE_ARCH=`arch | sed 's/^.*BSD\.//'`
 	echo ${UNAME_MACHINE_ARCH}-unknown-libertybsd${UNAME_RELEASE}
 	exit ;;
+    *:MidnightBSD:*:*)
+	echo ${UNAME_MACHINE}-unknown-midnightbsd${UNAME_RELEASE}
+	exit ;;
     *:ekkoBSD:*:*)
 	echo ${UNAME_MACHINE}-unknown-ekkobsd${UNAME_RELEASE}
 	exit ;;
@@ -259,6 +262,9 @@ case "${UNAME_MACHINE}:${UNAME_SYSTEM}:${UNAME_RELEASE}:${UNAME_VERSION}" in
     *:Sortix:*:*)
 	echo ${UNAME_MACHINE}-unknown-sortix
 	exit ;;
+    *:Redox:*:*)
+	echo ${UNAME_MACHINE}-unknown-redox
+	exit ;;
     alpha:OSF1:*:*)
 	case $UNAME_RELEASE in
 	*4.0)
@@ -315,15 +321,6 @@ case "${UNAME_MACHINE}:${UNAME_SYSTEM}:${UNAME_RELEASE}:${UNAME_VERSION}" in
 	exitcode=$?
 	trap '' 0
 	exit $exitcode ;;
-    Alpha\ *:Windows_NT*:*)
-	# How do we know it's Interix rather than the generic POSIX subsystem?
-	# Should we change UNAME_MACHINE based on the output of uname instead
-	# of the specific Alpha model?
-	echo alpha-pc-interix
-	exit ;;
-    21064:Windows_NT:50:3)
-	echo alpha-dec-winnt3.5
-	exit ;;
     Amiga*:UNIX_System_V:4.0:*)
 	echo m68k-unknown-sysv4
 	exit ;;
@@ -485,13 +482,13 @@ case "${UNAME_MACHINE}:${UNAME_SYSTEM}:${UNAME_RELEASE}:${UNAME_VERSION}" in
 #endif
 	#if defined (host_mips) && defined (MIPSEB)
 	#if defined (SYSTYPE_SYSV)
-	  printf ("mips-mips-riscos%ssysv\n", argv[1]); exit (0);
+	  printf ("mips-mips-riscos%ssysv\\n", argv[1]); exit (0);
 	#endif
 	#if defined (SYSTYPE_SVR4)
-	  printf ("mips-mips-riscos%ssvr4\n", argv[1]); exit (0);
+	  printf ("mips-mips-riscos%ssvr4\\n", argv[1]); exit (0);
 	#endif
 	#if defined (SYSTYPE_BSD43) || defined(SYSTYPE_BSD)
-	  printf ("mips-mips-riscos%sbsd\n", argv[1]); exit (0);
+	  printf ("mips-mips-riscos%sbsd\\n", argv[1]); exit (0);
 	#endif
 	#endif
 	  exit (-1);
@@ -614,7 +611,7 @@ EOF
     *:AIX:*:*)
 	echo rs6000-ibm-aix
 	exit ;;
-    ibmrt:4.4BSD:*|romp-ibm:BSD:*)
+    ibmrt:4.4BSD:*|romp-ibm:4.4BSD:*)
 	echo romp-ibm-bsd4.4
 	exit ;;
     ibmrt:*BSD:*|romp-ibm:BSD:*)            # covers RT/PC BSD and
@@ -635,8 +632,8 @@ EOF
     9000/[34678]??:HP-UX:*:*)
 	HPUX_REV=`echo ${UNAME_RELEASE}|sed -e 's/[^.]*.[0B]*//'`
 	case "${UNAME_MACHINE}" in
-	    9000/31? )            HP_ARCH=m68000 ;;
-	    9000/[34]?? )         HP_ARCH=m68k ;;
+	    9000/31?)            HP_ARCH=m68000 ;;
+	    9000/[34]??)         HP_ARCH=m68k ;;
 	    9000/[678][0-9][0-9])
 		if [ -x /usr/bin/getconf ]; then
 		    sc_cpu_version=`/usr/bin/getconf SC_CPU_VERSION 2>/dev/null`
@@ -749,7 +746,7 @@ EOF
 		{ echo "$SYSTEM_NAME"; exit; }
 	echo unknown-hitachi-hiuxwe2
 	exit ;;
-    9000/7??:4.3bsd:*:* | 9000/8?[79]:4.3bsd:*:* )
+    9000/7??:4.3bsd:*:* | 9000/8?[79]:4.3bsd:*:*)
 	echo hppa1.1-hp-bsd
 	exit ;;
     9000/8??:4.3bsd:*:*)
@@ -758,7 +755,7 @@ EOF
     *9??*:MPE/iX:*:* | *3000*:MPE/iX:*:*)
 	echo hppa1.0-hp-mpeix
 	exit ;;
-    hp7??:OSF1:*:* | hp8?[79]:OSF1:*:* )
+    hp7??:OSF1:*:* | hp8?[79]:OSF1:*:*)
 	echo hppa1.1-hp-osf
 	exit ;;
     hp8??:OSF1:*:*)
@@ -837,10 +834,11 @@ EOF
 	UNAME_PROCESSOR=`/usr/bin/uname -p`
 	case ${UNAME_PROCESSOR} in
 	    amd64)
-		echo x86_64-unknown-freebsd`echo ${UNAME_RELEASE}|sed -e 's/[-(].*//'` ;;
-	    *)
-		echo ${UNAME_PROCESSOR}-unknown-freebsd`echo ${UNAME_RELEASE}|sed -e 's/[-(].*//'` ;;
+		UNAME_PROCESSOR=x86_64 ;;
+	    i386)
+		UNAME_PROCESSOR=i586 ;;
 	esac
+	echo ${UNAME_PROCESSOR}-unknown-freebsd`echo ${UNAME_RELEASE}|sed -e 's/[-(].*//'`
 	exit ;;
     i*:CYGWIN*:*)
 	echo ${UNAME_MACHINE}-pc-cygwin
@@ -854,10 +852,6 @@ EOF
     *:MSYS*:*)
 	echo ${UNAME_MACHINE}-pc-msys
 	exit ;;
-    i*:windows32*:*)
-	# uname -m includes "-pc" on this system.
-	echo ${UNAME_MACHINE}-mingw32
-	exit ;;
     i*:PW*:*)
 	echo ${UNAME_MACHINE}-pc-pw32
 	exit ;;
@@ -873,27 +867,12 @@ EOF
 		echo ia64-unknown-interix${UNAME_RELEASE}
 		exit ;;
 	esac ;;
-    [345]86:Windows_95:* | [345]86:Windows_98:* | [345]86:Windows_NT:*)
-	echo i${UNAME_MACHINE}-pc-mks
-	exit ;;
-    8664:Windows_NT:*)
-	echo x86_64-pc-mks
-	exit ;;
-    i*:Windows_NT*:* | Pentium*:Windows_NT*:*)
-	# How do we know it's Interix rather than the generic POSIX subsystem?
-	# It also conflicts with pre-2.0 versions of AT&T UWIN. Should we
-	# UNAME_MACHINE based on the output of uname instead of i386?
-	echo i586-pc-interix
-	exit ;;
     i*:UWIN*:*)
 	echo ${UNAME_MACHINE}-pc-uwin
 	exit ;;
     amd64:CYGWIN*:*:* | x86_64:CYGWIN*:*:*)
 	echo x86_64-unknown-cygwin
 	exit ;;
-    p*:CYGWIN*:*)
-	echo powerpcle-unknown-cygwin
-	exit ;;
     prep*:SunOS:5.*:*)
 	echo powerpcle-unknown-solaris2`echo ${UNAME_RELEASE}|sed -e 's/[^.]*//'`
 	exit ;;
@@ -1096,7 +1075,7 @@ EOF
     i*86:*DOS:*:*)
 	echo ${UNAME_MACHINE}-pc-msdosdjgpp
 	exit ;;
-    i*86:*:4.*:* | i*86:SYSTEM_V:4.*:*)
+    i*86:*:4.*:*)
 	UNAME_REL=`echo ${UNAME_RELEASE} | sed 's/\/MP$//'`
 	if grep Novell /usr/include/link.h >/dev/null 2>/dev/null; then
 		echo ${UNAME_MACHINE}-univel-sysv${UNAME_REL}
@@ -1303,14 +1282,21 @@ EOF
 	if test `echo "$UNAME_RELEASE" | sed -e 's/\..*//'` -le 10 ; then
 	    if [ "$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
+		       (CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
+		       grep IS_64BIT_ARCH >/dev/null
 		then
 		    case $UNAME_PROCESSOR in
 			i386) UNAME_PROCESSOR=x86_64 ;;
 			powerpc) UNAME_PROCESSOR=powerpc64 ;;
 		    esac
 		fi
+		# On 10.4-10.6 one might compile for PowerPC via gcc -arch ppc
+		if (echo '#ifdef __POWERPC__'; echo IS_PPC; echo '#endif') | \
+		       (CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
+		       grep IS_PPC >/dev/null
+		then
+		    UNAME_PROCESSOR=powerpc
+		fi
 	    fi
 	elif test "$UNAME_PROCESSOR" = i386 ; then
 	    # Avoid executing cc on OS X 10.9, as it ships with a stub
@@ -1334,15 +1320,18 @@ EOF
     *:QNX:*:4*)
 	echo i386-pc-qnx
 	exit ;;
-    NEO-?:NONSTOP_KERNEL:*:*)
+    NEO-*:NONSTOP_KERNEL:*:*)
 	echo neo-tandem-nsk${UNAME_RELEASE}
 	exit ;;
     NSE-*:NONSTOP_KERNEL:*:*)
 	echo nse-tandem-nsk${UNAME_RELEASE}
 	exit ;;
-    NSR-?:NONSTOP_KERNEL:*:*)
+    NSR-*:NONSTOP_KERNEL:*:*)
 	echo nsr-tandem-nsk${UNAME_RELEASE}
 	exit ;;
+    NSX-*:NONSTOP_KERNEL:*:*)
+	echo nsx-tandem-nsk${UNAME_RELEASE}
+	exit ;;
     *:NonStop-UX:*:*)
 	echo mips-compaq-nonstopux
 	exit ;;
@@ -1414,16 +1403,28 @@ EOF
 	exit ;;
 esac
 
+echo "$0: unable to guess system type" >&2
+
+case "${UNAME_MACHINE}:${UNAME_SYSTEM}" in
+    mips:Linux | mips64:Linux)
+	# If we got here on MIPS GNU/Linux, output extra information.
+	cat >&2 <<EOF
+
+NOTE: MIPS GNU/Linux systems require a C compiler to fully recognize
+the system type. Please install a C compiler and try again.
+EOF
+	;;
+esac
+
 cat >&2 <<EOF
-$0: unable to guess system type
 
 This script (version $timestamp), has failed to recognize the
-operating system you are using. If your script is old, overwrite
-config.guess and config.sub with the latest versions from:
+operating system you are using. If your script is old, overwrite *all*
+copies of config.guess and config.sub with the latest versions from:
 
-  http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.guess
+  https://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.guess
 and
-  http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.sub
+  https://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.sub
 
 If $0 has already been updated, send the following data and any
 information you think might be pertinent to config-patches@gnu.org to
@@ -1455,7 +1456,7 @@ EOF
 exit 1
 
 # Local variables:
-# eval: (add-hook 'write-file-hooks 'time-stamp)
+# eval: (add-hook 'write-file-functions 'time-stamp)
 # time-stamp-start: "timestamp='"
 # time-stamp-format: "%:y-%02m-%02d"
 # time-stamp-end: "'"
diff --git a/mk/gnu-config/config.sub b/mk/gnu-config/config.sub
index 7e792b4ae17..00f68b8e5f3 100755
--- a/mk/gnu-config/config.sub
+++ b/mk/gnu-config/config.sub
@@ -2,7 +2,7 @@
 # Configuration validation subroutine script.
 #   Copyright 1992-2017 Free Software Foundation, Inc.
 
-timestamp='2017-01-01'
+timestamp='2017-11-23'
 
 # 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
@@ -15,7 +15,7 @@ timestamp='2017-01-01'
 # General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
-# along with this program; if not, see <http://www.gnu.org/licenses/>.
+# along with this program; if not, see <https://www.gnu.org/licenses/>.
 #
 # As a special exception to the GNU General Public License, if you
 # distribute this file as part of a program that contains a
@@ -33,7 +33,7 @@ timestamp='2017-01-01'
 # Otherwise, we print the canonical config type on stdout and succeed.
 
 # You can get the latest version of this script from:
-# http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.sub
+# https://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.sub
 
 # This file is supposed to be the same for all GNU packages
 # and recognize all the CPU types, system types and aliases
@@ -57,7 +57,7 @@ Usage: $0 [OPTION] CPU-MFR-OPSYS or ALIAS
 
 Canonicalize a configuration name.
 
-Operation modes:
+Options:
   -h, --help         print this help, then exit
   -t, --time-stamp   print date of last modification, then exit
   -v, --version      print version number, then exit
@@ -229,9 +229,6 @@ case $os in
 	-ptx*)
 		basic_machine=`echo $1 | sed -e 's/86-.*/86-sequent/'`
 		;;
-	-windowsnt*)
-		os=`echo $os | sed -e 's/windowsnt/winnt/'`
-		;;
 	-psos*)
 		os=-psos
 		;;
@@ -263,7 +260,7 @@ case $basic_machine in
 	| fido | fr30 | frv | ft32 \
 	| h8300 | h8500 | hppa | hppa1.[01] | hppa2.0 | hppa2.0[nw] | hppa64 \
 	| hexagon \
-	| i370 | i860 | i960 | ia64 \
+	| i370 | i860 | i960 | ia16 | ia64 \
 	| ip2k | iq2000 \
 	| k1om \
 	| le32 | le64 \
@@ -315,7 +312,7 @@ case $basic_machine in
 	| ubicom32 \
 	| v850 | v850e | v850e1 | v850e2 | v850es | v850e2v3 \
 	| visium \
-	| we32k \
+	| wasm32 \
 	| x86 | xc16x | xstormy16 | xtensa \
 	| z8k | z80)
 		basic_machine=$basic_machine-unknown
@@ -388,7 +385,7 @@ case $basic_machine in
 	| h8300-* | h8500-* \
 	| hppa-* | hppa1.[01]-* | hppa2.0-* | hppa2.0[nw]-* | hppa64-* \
 	| hexagon-* \
-	| i*86-* | i860-* | i960-* | ia64-* \
+	| i*86-* | i860-* | i960-* | ia16-* | ia64-* \
 	| ip2k-* | iq2000-* \
 	| k1om-* \
 	| le32-* | le64-* \
@@ -446,6 +443,7 @@ case $basic_machine in
 	| v850-* | v850e-* | v850e1-* | v850es-* | v850e2-* | v850e2v3-* \
 	| vax-* \
 	| visium-* \
+	| wasm32-* \
 	| we32k-* \
 	| x86-* | x86_64-* | xc16x-* | xps100-* \
 	| xstormy16-* | xtensa*-* \
@@ -641,7 +639,7 @@ case $basic_machine in
 		basic_machine=rs6000-bull
 		os=-bosx
 		;;
-	dpx2* | dpx2*-bull)
+	dpx2*)
 		basic_machine=m68k-bull
 		os=-sysv3
 		;;
@@ -903,7 +901,7 @@ case $basic_machine in
 		basic_machine=v70-nec
 		os=-sysv
 		;;
-	next | m*-next )
+	next | m*-next)
 		basic_machine=m68k-next
 		case $os in
 		    -nextstep* )
@@ -948,6 +946,9 @@ case $basic_machine in
 	nsr-tandem)
 		basic_machine=nsr-tandem
 		;;
+	nsx-tandem)
+		basic_machine=nsx-tandem
+		;;
 	op50n-* | op60c-*)
 		basic_machine=hppa1.1-oki
 		os=-proelf
@@ -1243,6 +1244,9 @@ case $basic_machine in
 		basic_machine=a29k-wrs
 		os=-vxworks
 		;;
+	wasm32)
+		basic_machine=wasm32-unknown
+		;;
 	w65*)
 		basic_machine=w65-wdc
 		os=-none
@@ -1251,6 +1255,9 @@ case $basic_machine in
 		basic_machine=hppa1.1-winbond
 		os=-proelf
 		;;
+	x64)
+		basic_machine=x86_64-pc
+		;;
 	xbox)
 		basic_machine=i686-pc
 		os=-mingw32
@@ -1358,8 +1365,8 @@ esac
 if [ x"$os" != x"" ]
 then
 case $os in
-	# First match some system type aliases
-	# that might get confused with valid system types.
+	# First match some system type aliases that might get confused
+	# with valid system types.
 	# -solaris* is a basic system type, with this one exception.
 	-auroraux)
 		os=-auroraux
@@ -1379,9 +1386,9 @@ case $os in
 	-gnu/linux*)
 		os=`echo $os | sed -e 's|gnu/linux|linux-gnu|'`
 		;;
-	# First accept the basic system types.
+	# Now accept the basic system types.
 	# The portable systems comes first.
-	# Each alternative MUST END IN A *, to match a version number.
+	# Each alternative MUST end in a * to match a version number.
 	# -sysv* is not here because it comes later, after sysvr4.
 	-gnu* | -bsd* | -mach* | -minix* | -genix* | -ultrix* | -irix* \
 	      | -*vms* | -sco* | -esix* | -isc* | -aix* | -cnk* | -sunos | -sunos[34]*\
@@ -1484,7 +1491,7 @@ case $os in
 	-nova*)
 		os=-rtmk-nova
 		;;
-	-ns2 )
+	-ns2)
 		os=-nextstep2
 		;;
 	-nsk*)
@@ -1539,6 +1546,19 @@ case $os in
 	-dicos*)
 		os=-dicos
 		;;
+	-pikeos*)
+		# Until real need of OS specific support for
+		# particular features comes up, bare metal
+		# configurations are quite functional.
+		case $basic_machine in
+		    arm*)
+			os=-eabi
+			;;
+		    *)
+			os=-elf
+			;;
+		esac
+		;;
 	-nacl*)
 		;;
 	-ios)
@@ -1686,7 +1706,7 @@ case $basic_machine in
 	m88k-omron*)
 		os=-luna
 		;;
-	*-next )
+	*-next)
 		os=-nextstep
 		;;
 	*-sequent)
@@ -1821,7 +1841,7 @@ echo $basic_machine$os
 exit
 
 # Local variables:
-# eval: (add-hook 'write-file-hooks 'time-stamp)
+# eval: (add-hook 'write-file-functions 'time-stamp)
 # time-stamp-start: "timestamp='"
 # time-stamp-format: "%:y-%02m-%02d"
 # time-stamp-end: "'"
diff --git a/mk/gnu-config/missing b/mk/gnu-config/missing
index 9a5564823de..46d7c7e2308 100755
--- a/mk/gnu-config/missing
+++ b/mk/gnu-config/missing
@@ -1,10 +1,10 @@
 #! /bin/sh
-# Common stub for a few missing GNU programs while installing.
+# Common wrapper for a few potentially missing GNU programs.
 
-scriptversion=2012-01-06.18; # UTC
+scriptversion=2017-09-16.17; # UTC
 
-# Copyright (C) 1996-2012 Free Software Foundation, Inc.
-# Originally by Fran,cois Pinard <pinard@iro.umontreal.ca>, 1996.
+# Copyright (C) 1996-2017 Free Software Foundation, Inc.
+# Originally written by Fran,cois Pinard <pinard@iro.umontreal.ca>, 1996.
 
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -17,7 +17,7 @@ scriptversion=2012-01-06.18; # UTC
 # GNU General Public License for more details.
 
 # You should have received a copy of the GNU General Public License
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 # As a special exception to the GNU General Public License, if you
 # distribute this file as part of a program that contains a
@@ -29,61 +29,33 @@ if test $# -eq 0; then
   exit 1
 fi
 
-run=:
-sed_output='s/.* --output[ =]\([^ ]*\).*/\1/p'
-sed_minuso='s/.* -o \([^ ]*\).*/\1/p'
-
-# In the cases where this matters, 'missing' is being run in the
-# srcdir already.
-if test -f configure.ac; then
-  configure_ac=configure.ac
-else
-  configure_ac=configure.in
-fi
+case $1 in
 
-msg="missing on your system"
+  --is-lightweight)
+    # Used by our autoconf macros to check whether the available missing
+    # script is modern enough.
+    exit 0
+    ;;
 
-case $1 in
---run)
-  # Try to run requested program, and just exit if it succeeds.
-  run=
-  shift
-  "$@" && exit 0
-  # Exit code 63 means version mismatch.  This often happens
-  # when the user try to use an ancient version of a tool on
-  # a file that requires a minimum version.  In this case we
-  # we should proceed has if the program had been absent, or
-  # if --run hadn't been passed.
-  if test $? = 63; then
-    run=:
-    msg="probably too old"
-  fi
-  ;;
+  --run)
+    # Back-compat with the calling convention used by older automake.
+    shift
+    ;;
 
   -h|--h|--he|--hel|--help)
     echo "\
 $0 [OPTION]... PROGRAM [ARGUMENT]...
 
-Handle 'PROGRAM [ARGUMENT]...' for when PROGRAM is missing, or return an
-error status if there is no known handling for PROGRAM.
+Run 'PROGRAM [ARGUMENT]...', returning a proper advice when this fails due
+to PROGRAM being missing or too old.
 
 Options:
   -h, --help      display this help and exit
   -v, --version   output version information and exit
-  --run           try to run the given command, and emulate it if it fails
 
 Supported PROGRAM values:
-  aclocal      touch file 'aclocal.m4'
-  autoconf     touch file 'configure'
-  autoheader   touch file 'config.h.in'
-  autom4te     touch the output file, or create a stub one
-  automake     touch all 'Makefile.in' files
-  bison        create 'y.tab.[ch]', if possible, from existing .[ch]
-  flex         create 'lex.yy.c', if possible, from existing .c
-  help2man     touch the output file
-  lex          create 'lex.yy.c', if possible, from existing .c
-  makeinfo     touch the output file
-  yacc         create 'y.tab.[ch]', if possible, from existing .[ch]
+  aclocal   autoconf  autoheader   autom4te  automake  makeinfo
+  bison     yacc      flex         lex       help2man
 
 Version suffixes to PROGRAM as well as the prefixes 'gnu-', 'gnu', and
 'g' are ignored when checking the name.
@@ -98,233 +70,146 @@ Send bug reports to <bug-automake@gnu.org>."
     ;;
 
   -*)
-    echo 1>&2 "$0: Unknown '$1' option"
+    echo 1>&2 "$0: unknown '$1' option"
     echo 1>&2 "Try '$0 --help' for more information"
     exit 1
     ;;
 
 esac
 
-# normalize program name to check for.
-program=`echo "$1" | sed '
-  s/^gnu-//; t
-  s/^gnu//; t
-  s/^g//; t'`
-
-# Now exit if we have it, but it failed.  Also exit now if we
-# don't have it and --version was passed (most likely to detect
-# the program).  This is about non-GNU programs, so use $1 not
-# $program.
-case $1 in
-  lex*|yacc*)
-    # Not GNU programs, they don't have --version.
-    ;;
-
-  *)
-    if test -z "$run" && ($1 --version) > /dev/null 2>&1; then
-       # We have it, but it failed.
-       exit 1
-    elif test "x$2" = "x--version" || test "x$2" = "x--help"; then
-       # Could not run --version or --help.  This is probably someone
-       # running '$TOOL --version' or '$TOOL --help' to check whether
-       # $TOOL exists and not knowing $TOOL uses missing.
-       exit 1
-    fi
-    ;;
-esac
-
-# If it does not exist, or fails to run (possibly an outdated version),
-# try to emulate it.
-case $program in
-  aclocal*)
-    echo 1>&2 "\
-WARNING: '$1' is $msg.  You should only need it if
-         you modified 'acinclude.m4' or '${configure_ac}'.  You might want
-         to install the Automake and Perl packages.  Grab them from
-         any GNU archive site."
-    touch aclocal.m4
-    ;;
-
-  autoconf*)
-    echo 1>&2 "\
-WARNING: '$1' is $msg.  You should only need it if
-         you modified '${configure_ac}'.  You might want to install the
-         Autoconf and GNU m4 packages.  Grab them from any GNU
-         archive site."
-    touch configure
-    ;;
-
-  autoheader*)
-    echo 1>&2 "\
-WARNING: '$1' is $msg.  You should only need it if
-         you modified 'acconfig.h' or '${configure_ac}'.  You might want
-         to install the Autoconf and GNU m4 packages.  Grab them
-         from any GNU archive site."
-    files=`sed -n 's/^[ ]*A[CM]_CONFIG_HEADER(\([^)]*\)).*/\1/p' ${configure_ac}`
-    test -z "$files" && files="config.h"
-    touch_files=
-    for f in $files; do
-      case $f in
-      *:*) touch_files="$touch_files "`echo "$f" |
-				       sed -e 's/^[^:]*://' -e 's/:.*//'`;;
-      *) touch_files="$touch_files $f.in";;
-      esac
-    done
-    touch $touch_files
-    ;;
-
-  automake*)
-    echo 1>&2 "\
-WARNING: '$1' is $msg.  You should only need it if
-         you modified 'Makefile.am', 'acinclude.m4' or '${configure_ac}'.
-         You might want to install the Automake and Perl packages.
-         Grab them from any GNU archive site."
-    find . -type f -name Makefile.am -print |
-	   sed 's/\.am$/.in/' |
-	   while read f; do touch "$f"; done
-    ;;
-
-  autom4te*)
-    echo 1>&2 "\
-WARNING: '$1' is needed, but is $msg.
-         You might have modified some files without having the
-         proper tools for further handling them.
-         You can get '$1' as part of Autoconf from any GNU
-         archive site."
-
-    file=`echo "$*" | sed -n "$sed_output"`
-    test -z "$file" && file=`echo "$*" | sed -n "$sed_minuso"`
-    if test -f "$file"; then
-	touch $file
-    else
-	test -z "$file" || exec >$file
-	echo "#! /bin/sh"
-	echo "# Created by GNU Automake missing as a replacement of"
-	echo "#  $ $@"
-	echo "exit 0"
-	chmod +x $file
-	exit 1
-    fi
-    ;;
-
-  bison*|yacc*)
-    echo 1>&2 "\
-WARNING: '$1' $msg.  You should only need it if
-         you modified a '.y' file.  You may need the Bison package
-         in order for those modifications to take effect.  You can get
-         Bison from any GNU archive site."
-    rm -f y.tab.c y.tab.h
-    if test $# -ne 1; then
-        eval LASTARG=\${$#}
-	case $LASTARG in
-	*.y)
-	    SRCFILE=`echo "$LASTARG" | sed 's/y$/c/'`
-	    if test -f "$SRCFILE"; then
-	         cp "$SRCFILE" y.tab.c
-	    fi
-	    SRCFILE=`echo "$LASTARG" | sed 's/y$/h/'`
-	    if test -f "$SRCFILE"; then
-	         cp "$SRCFILE" y.tab.h
-	    fi
-	  ;;
-	esac
-    fi
-    if test ! -f y.tab.h; then
-	echo >y.tab.h
-    fi
-    if test ! -f y.tab.c; then
-	echo 'main() { return 0; }' >y.tab.c
-    fi
-    ;;
-
-  lex*|flex*)
-    echo 1>&2 "\
-WARNING: '$1' is $msg.  You should only need it if
-         you modified a '.l' file.  You may need the Flex package
-         in order for those modifications to take effect.  You can get
-         Flex from any GNU archive site."
-    rm -f lex.yy.c
-    if test $# -ne 1; then
-        eval LASTARG=\${$#}
-	case $LASTARG in
-	*.l)
-	    SRCFILE=`echo "$LASTARG" | sed 's/l$/c/'`
-	    if test -f "$SRCFILE"; then
-	         cp "$SRCFILE" lex.yy.c
-	    fi
-	  ;;
-	esac
-    fi
-    if test ! -f lex.yy.c; then
-	echo 'main() { return 0; }' >lex.yy.c
-    fi
-    ;;
-
-  help2man*)
-    echo 1>&2 "\
-WARNING: '$1' is $msg.  You should only need it if
-	 you modified a dependency of a manual page.  You may need the
-	 Help2man package in order for those modifications to take
-	 effect.  You can get Help2man from any GNU archive site."
-
-    file=`echo "$*" | sed -n "$sed_output"`
-    test -z "$file" && file=`echo "$*" | sed -n "$sed_minuso"`
-    if test -f "$file"; then
-	touch $file
-    else
-	test -z "$file" || exec >$file
-	echo ".ab help2man is required to generate this page"
-	exit $?
-    fi
-    ;;
-
-  makeinfo*)
-    echo 1>&2 "\
-WARNING: '$1' is $msg.  You should only need it if
-         you modified a '.texi' or '.texinfo' file, or any other file
-         indirectly affecting the aspect of the manual.  The spurious
-         call might also be the consequence of using a buggy 'make' (AIX,
-         DU, IRIX).  You might want to install the Texinfo package or
-         the GNU make package.  Grab either from any GNU archive site."
-    # The file to touch is that specified with -o ...
-    file=`echo "$*" | sed -n "$sed_output"`
-    test -z "$file" && file=`echo "$*" | sed -n "$sed_minuso"`
-    if test -z "$file"; then
-      # ... or it is the one specified with @setfilename ...
-      infile=`echo "$*" | sed 's/.* \([^ ]*\) *$/\1/'`
-      file=`sed -n '
-	/^@setfilename/{
-	  s/.* \([^ ]*\) *$/\1/
-	  p
-	  q
-	}' $infile`
-      # ... or it is derived from the source name (dir/f.texi becomes f.info)
-      test -z "$file" && file=`echo "$infile" | sed 's,.*/,,;s,.[^.]*$,,'`.info
-    fi
-    # If the file does not exist, the user really needs makeinfo;
-    # let's fail without touching anything.
-    test -f $file || exit 1
-    touch $file
-    ;;
+# Run the given program, remember its exit status.
+"$@"; st=$?
+
+# If it succeeded, we are done.
+test $st -eq 0 && exit 0
+
+# Also exit now if we it failed (or wasn't found), and '--version' was
+# passed; such an option is passed most likely to detect whether the
+# program is present and works.
+case $2 in --version|--help) exit $st;; esac
+
+# Exit code 63 means version mismatch.  This often happens when the user
+# tries to use an ancient version of a tool on a file that requires a
+# minimum version.
+if test $st -eq 63; then
+  msg="probably too old"
+elif test $st -eq 127; then
+  # Program was missing.
+  msg="missing on your system"
+else
+  # Program was found and executed, but failed.  Give up.
+  exit $st
+fi
 
-  *)
-    echo 1>&2 "\
-WARNING: '$1' is needed, and is $msg.
-         You might have modified some files without having the
-         proper tools for further handling them.  Check the 'README' file,
-         it often tells you about the needed prerequisites for installing
-         this package.  You may also peek at any GNU archive site, in case
-         some other package would contain this missing '$1' program."
-    exit 1
+perl_URL=http://www.perl.org/
+flex_URL=http://flex.sourceforge.net/
+gnu_software_URL=https://www.gnu.org/software
+
+program_details ()
+{
+  case $1 in
+    aclocal|automake)
+      echo "The '$1' program is part of the GNU Automake package:"
+      echo "<$gnu_software_URL/automake>"
+      echo "It also requires GNU Autoconf, GNU m4 and Perl in order to run:"
+      echo "<$gnu_software_URL/autoconf>"
+      echo "<$gnu_software_URL/m4/>"
+      echo "<$perl_URL>"
+      ;;
+    autoconf|autom4te|autoheader)
+      echo "The '$1' program is part of the GNU Autoconf package:"
+      echo "<$gnu_software_URL/autoconf/>"
+      echo "It also requires GNU m4 and Perl in order to run:"
+      echo "<$gnu_software_URL/m4/>"
+      echo "<$perl_URL>"
+      ;;
+  esac
+}
+
+give_advice ()
+{
+  # Normalize program name to check for.
+  normalized_program=`echo "$1" | sed '
+    s/^gnu-//; t
+    s/^gnu//; t
+    s/^g//; t'`
+
+  printf '%s\n' "'$1' is $msg."
+
+  configure_deps="'configure.ac' or m4 files included by 'configure.ac'"
+  case $normalized_program in
+    autoconf*)
+      echo "You should only need it if you modified 'configure.ac',"
+      echo "or m4 files included by it."
+      program_details 'autoconf'
+      ;;
+    autoheader*)
+      echo "You should only need it if you modified 'acconfig.h' or"
+      echo "$configure_deps."
+      program_details 'autoheader'
+      ;;
+    automake*)
+      echo "You should only need it if you modified 'Makefile.am' or"
+      echo "$configure_deps."
+      program_details 'automake'
+      ;;
+    aclocal*)
+      echo "You should only need it if you modified 'acinclude.m4' or"
+      echo "$configure_deps."
+      program_details 'aclocal'
+      ;;
+   autom4te*)
+      echo "You might have modified some maintainer files that require"
+      echo "the 'autom4te' program to be rebuilt."
+      program_details 'autom4te'
+      ;;
+    bison*|yacc*)
+      echo "You should only need it if you modified a '.y' file."
+      echo "You may want to install the GNU Bison package:"
+      echo "<$gnu_software_URL/bison/>"
+      ;;
+    lex*|flex*)
+      echo "You should only need it if you modified a '.l' file."
+      echo "You may want to install the Fast Lexical Analyzer package:"
+      echo "<$flex_URL>"
+      ;;
+    help2man*)
+      echo "You should only need it if you modified a dependency" \
+           "of a man page."
+      echo "You may want to install the GNU Help2man package:"
+      echo "<$gnu_software_URL/help2man/>"
     ;;
-esac
-
-exit 0
+    makeinfo*)
+      echo "You should only need it if you modified a '.texi' file, or"
+      echo "any other file indirectly affecting the aspect of the manual."
+      echo "You might want to install the Texinfo package:"
+      echo "<$gnu_software_URL/texinfo/>"
+      echo "The spurious makeinfo call might also be the consequence of"
+      echo "using a buggy 'make' (AIX, DU, IRIX), in which case you might"
+      echo "want to install GNU make:"
+      echo "<$gnu_software_URL/make/>"
+      ;;
+    *)
+      echo "You might have modified some files without having the proper"
+      echo "tools for further handling them.  Check the 'README' file, it"
+      echo "often tells you about the needed prerequisites for installing"
+      echo "this package.  You may also peek at any GNU archive site, in"
+      echo "case some other package contains this missing '$1' program."
+      ;;
+  esac
+}
+
+give_advice "$1" | sed -e '1s/^/WARNING: /' \
+                       -e '2,$s/^/         /' >&2
+
+# Propagate the correct exit status (expected to be 127 for a program
+# not found, 63 for a program that failed due to version mismatch).
+exit $st
 
 # Local variables:
 # eval: (add-hook 'write-file-hooks 'time-stamp)
 # time-stamp-start: "scriptversion="
 # time-stamp-format: "%:y-%02m-%02d.%02H"
-# time-stamp-time-zone: "UTC"
+# time-stamp-time-zone: "UTC0"
 # time-stamp-end: "; # UTC"
 # End: