Update and clean up autoconf template files.
authorRichard Kreckel <kreckel@ginac.de>
Fri, 5 Nov 2021 13:47:53 +0000 (14:47 +0100)
committerRichard Kreckel <kreckel@ginac.de>
Fri, 5 Nov 2021 13:47:53 +0000 (14:47 +0100)
This is needed for compatibility with newer autoconf:
* Removed macro GINAC_STD_CXX_HEADERS (we use AX_CXX_COMPILE_STDCXX).
* Updated m4/* files from upstream.
* Ran autoupdate on acinclude.m4 and configure.ac.

Tested successfully with autoconf 1.69 and 1.71.

acinclude.m4
configure.ac
m4/host-cpu-c-abi.m4
m4/lib-ld.m4
m4/lib-link.m4
m4/lib-prefix.m4

index 53b45e5a9e8c0ac36712bc13206561eb6a40151e..35cd3862fefe3f331e6a72b93e947b9385a63416 100644 (file)
@@ -22,48 +22,6 @@ define(GINAC_GET_VERSION,
 define(GINAC_GET_LTVERSION,
 [GINAC_HEADER_GETVAL(GINAC_LT_$1,[ginac/version.h])])
 
-dnl Usage: GINAC_STD_CXX_HEADERS
-dnl Check for standard C++ headers, bail out if something is missing.
-AC_DEFUN([GINAC_STD_CXX_HEADERS], [
-AC_CACHE_CHECK([for standard C++ header files], [ginac_cv_std_cxx_headers], [
-       ginac_cv_std_cxx_headers="no"
-       AC_LANG_PUSH([C++])
-       AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-               #include <algorithm>
-               #include <cstddef>
-               #include <cstdio>
-               #include <cstdlib>
-               #include <cstring>
-               #include <cstdint>
-               #include <ctime>
-               #include <fstream>
-               #include <functional>
-               #include <iomanip>
-               #include <ios>
-               #include <iosfwd>
-               #include <iostream>
-               #include <iterator>
-               #include <limits>
-               #include <list>
-               #include <map>
-               #include <memory>
-               #include <numeric>
-               #include <ostream>
-               #include <set>
-               #include <sstream>
-               #include <stack>
-               #include <stdexcept>
-               #include <string>
-               #include <typeinfo>
-               #include <utility>
-               #include <vector>
-               ]])], [ginac_cv_std_cxx_headers="yes"])
-       AC_LANG_POP([C++])])
-if test "${ginac_cv_std_cxx_headers}" != "yes"; then
-       AC_MSG_ERROR([Standard ISO C++ headers are missing])
-fi
-])
-
 dnl Usage: GINAC_LIBREADLINE
 dnl
 dnl Check if GNU readline library and headers are avialable.
@@ -181,13 +139,13 @@ fi])
 AC_DEFUN([GINAC_HAVE_RUSAGE],
 [AC_CACHE_CHECK([whether struct rusage is declared in <sys/resource.h>],
 ac_cv_have_rusage,
- [AC_TRY_COMPILE([#include <sys/times.h>
-                  #include <sys/resource.h>],
-                  [struct rusage resUsage;
-                   getrusage(RUSAGE_SELF, &resUsage);
-                   return 0;],
-                 [ac_cv_have_rusage=yes],
-                 [ac_cv_have_rusage=no])
+ [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/times.h>
+                                       #include <sys/resource.h>]],
+                                     [[struct rusage resUsage;
+                                       getrusage(RUSAGE_SELF, &resUsage);
+                                       return 0;]])],
+                    [ac_cv_have_rusage=yes],
+                    [ac_cv_have_rusage=no])
 ])
 CONFIG_RUSAGE="no"
 if test "$ac_cv_have_rusage" = yes; then
index 3529a65ec91f6b6796fa24c60d1b5eaf56d7e873..550214817ea51ab91103c94ba379134c843c0dcc 100644 (file)
@@ -11,8 +11,8 @@ m4_define([ginac_lt_current], GINAC_GET_LTVERSION([CURRENT]))
 m4_define([ginac_lt_age], GINAC_GET_LTVERSION([AGE]))
 m4_define([ginac_lt_revision], GINAC_GET_LTVERSION([REVISION]))
 
-AC_INIT([GiNaC], ginac_version, [ginac-list@ginac.de], [ginac], [https://www.ginac.de/])
-AC_PREREQ(2.59)
+AC_INIT([GiNaC], [ginac_version], [ginac-list@ginac.de], [ginac], [https://www.ginac.de/])
+AC_PREREQ([2.59])
 AC_CONFIG_SRCDIR(ginac/basic.cpp)
 AC_CONFIG_AUX_DIR([config])
 AC_CONFIG_HEADERS([config/config.h])
@@ -28,8 +28,8 @@ dnl Check for the compiler and all the utilities needed for the build.
 AC_PROG_CXX
 AC_PROG_CXXCPP
 AC_PROG_INSTALL
-AM_PROG_LIBTOOL
-AC_PROG_LEX
+LT_INIT
+AC_PROG_LEX([yywrap])
 AC_PROG_YACC
 AC_PATH_PROG(YACCEXE, $YACC, "")
 AS_IF([test "x$LEX" = "x:" -a ! -f $srcdir/ginsh/ginsh_lexer.cpp],
@@ -41,9 +41,6 @@ dnl Switch to C++ language mode for the following libraries and headers.
 AC_LANG([C++])
 AX_CXX_COMPILE_STDCXX([11])
 
-dnl Make sure all the necessary standard headers are installed on the system.
-GINAC_STD_CXX_HEADERS
-
 dnl We need to have CLN installed.
 PKG_CHECK_MODULES(CLN, cln >= 1.2.2)
 AC_LIB_LINKFLAGS_FROM_LIBS([CLN_RPATH], [$CLN_LIBS])
index 6db2aa25aeaff9ce9bb0722ea747a65df6cbf628..64e28b1d34ae5bcfd64f24ed6495eae7519e7462 100644 (file)
@@ -1,5 +1,5 @@
-# host-cpu-c-abi.m4 serial 13
-dnl Copyright (C) 2002-2020 Free Software Foundation, Inc.
+# host-cpu-c-abi.m4 serial 14
+dnl Copyright (C) 2002-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -211,7 +211,7 @@ changequote([,])dnl
          # be generating 64-bit code.
          AC_COMPILE_IFELSE(
            [AC_LANG_SOURCE(
-              [[#if defined __powerpc64__ || defined _ARCH_PPC64
+              [[#if defined __powerpc64__ || defined __LP64__
                  int ok;
                 #else
                  error fail
@@ -605,7 +605,7 @@ changequote([,])dnl
            # be generating 64-bit code.
            AC_COMPILE_IFELSE(
              [AC_LANG_SOURCE(
-                [[#if defined __powerpc64__ || defined _ARCH_PPC64
+                [[#if defined __powerpc64__ || defined __LP64__
                    int ok;
                   #else
                    error fail
index a18719630d59538c0c03a8677aca2adcd63313aa..076358d5d5c1a8e034e1c893259dc38286e55b27 100644 (file)
@@ -1,5 +1,5 @@
-# lib-ld.m4 serial 9
-dnl Copyright (C) 1996-2003, 2009-2019 Free Software Foundation, Inc.
+# lib-ld.m4 serial 10
+dnl Copyright (C) 1996-2003, 2009-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -122,7 +122,7 @@ else
       *-*-aix*)
         AC_COMPILE_IFELSE(
           [AC_LANG_SOURCE(
-             [[#if defined __powerpc64__ || defined _ARCH_PPC64
+             [[#if defined __powerpc64__ || defined __LP64__
                 int ok;
                #else
                 error fail
index 0ff10731facd82df2d2e94453bbbf44b0d475965..787efab2d2c8dc17d5ac23c5cb03ed3056fafa52 100644 (file)
@@ -1,5 +1,5 @@
-# lib-link.m4 serial 28
-dnl Copyright (C) 2001-2019 Free Software Foundation, Inc.
+# lib-link.m4 serial 32
+dnl Copyright (C) 2001-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -192,6 +192,8 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
   AC_LIB_WITH_FINAL_PREFIX([
     eval additional_includedir=\"$includedir\"
     eval additional_libdir=\"$libdir\"
+    eval additional_libdir2=\"$exec_prefix/$acl_libdirstem2\"
+    eval additional_libdir3=\"$exec_prefix/$acl_libdirstem3\"
   ])
   AC_ARG_WITH(PACK[-prefix],
 [[  --with-]]PACK[[-prefix[=DIR]  search for ]PACKLIBS[ in DIR/include and DIR/lib
@@ -204,17 +206,23 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
         AC_LIB_WITH_FINAL_PREFIX([
           eval additional_includedir=\"$includedir\"
           eval additional_libdir=\"$libdir\"
+          eval additional_libdir2=\"$exec_prefix/$acl_libdirstem2\"
+          eval additional_libdir3=\"$exec_prefix/$acl_libdirstem3\"
         ])
       else
         additional_includedir="$withval/include"
         additional_libdir="$withval/$acl_libdirstem"
-        if test "$acl_libdirstem2" != "$acl_libdirstem" \
-           && test ! -d "$withval/$acl_libdirstem"; then
-          additional_libdir="$withval/$acl_libdirstem2"
-        fi
+        additional_libdir2="$withval/$acl_libdirstem2"
+        additional_libdir3="$withval/$acl_libdirstem3"
       fi
     fi
 ])
+  if test "X$additional_libdir2" = "X$additional_libdir"; then
+    additional_libdir2=
+  fi
+  if test "X$additional_libdir3" = "X$additional_libdir"; then
+    additional_libdir3=
+  fi
   dnl Search the library and its dependencies in $additional_libdir and
   dnl $LDFLAGS. Using breadth-first-seach.
   LIB[]NAME=
@@ -270,48 +278,54 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
             shrext=
           fi
           if test $use_additional = yes; then
-            dir="$additional_libdir"
-            dnl The same code as in the loop below:
-            dnl First look for a shared library.
-            if test -n "$acl_shlibext"; then
-              if test -f "$dir/$libname$shrext"; then
-                found_dir="$dir"
-                found_so="$dir/$libname$shrext"
-              else
-                if test "$acl_library_names_spec" = '$libname$shrext$versuffix'; then
-                  ver=`(cd "$dir" && \
-                        for f in "$libname$shrext".*; do echo "$f"; done \
-                        | sed -e "s,^$libname$shrext\\\\.,," \
-                        | sort -t '.' -n -r -k1,1 -k2,2 -k3,3 -k4,4 -k5,5 \
-                        | sed 1q ) 2>/dev/null`
-                  if test -n "$ver" && test -f "$dir/$libname$shrext.$ver"; then
-                    found_dir="$dir"
-                    found_so="$dir/$libname$shrext.$ver"
+            for additional_libdir_variable in additional_libdir additional_libdir2 additional_libdir3; do
+              if test "X$found_dir" = "X"; then
+                eval dir=\$$additional_libdir_variable
+                if test -n "$dir"; then
+                  dnl The same code as in the loop below:
+                  dnl First look for a shared library.
+                  if test -n "$acl_shlibext"; then
+                    if test -f "$dir/$libname$shrext" && acl_is_expected_elfclass < "$dir/$libname$shrext"; then
+                      found_dir="$dir"
+                      found_so="$dir/$libname$shrext"
+                    else
+                      if test "$acl_library_names_spec" = '$libname$shrext$versuffix'; then
+                        ver=`(cd "$dir" && \
+                              for f in "$libname$shrext".*; do echo "$f"; done \
+                              | sed -e "s,^$libname$shrext\\\\.,," \
+                              | sort -t '.' -n -r -k1,1 -k2,2 -k3,3 -k4,4 -k5,5 \
+                              | sed 1q ) 2>/dev/null`
+                        if test -n "$ver" && test -f "$dir/$libname$shrext.$ver" && acl_is_expected_elfclass < "$dir/$libname$shrext.$ver"; then
+                          found_dir="$dir"
+                          found_so="$dir/$libname$shrext.$ver"
+                        fi
+                      else
+                        eval library_names=\"$acl_library_names_spec\"
+                        for f in $library_names; do
+                          if test -f "$dir/$f" && acl_is_expected_elfclass < "$dir/$f"; then
+                            found_dir="$dir"
+                            found_so="$dir/$f"
+                            break
+                          fi
+                        done
+                      fi
+                    fi
                   fi
-                else
-                  eval library_names=\"$acl_library_names_spec\"
-                  for f in $library_names; do
-                    if test -f "$dir/$f"; then
+                  dnl Then look for a static library.
+                  if test "X$found_dir" = "X"; then
+                    if test -f "$dir/$libname.$acl_libext" && ${AR-ar} -p "$dir/$libname.$acl_libext" | acl_is_expected_elfclass; then
                       found_dir="$dir"
-                      found_so="$dir/$f"
-                      break
+                      found_a="$dir/$libname.$acl_libext"
                     fi
-                  done
+                  fi
+                  if test "X$found_dir" != "X"; then
+                    if test -f "$dir/$libname.la"; then
+                      found_la="$dir/$libname.la"
+                    fi
+                  fi
                 fi
               fi
-            fi
-            dnl Then look for a static library.
-            if test "X$found_dir" = "X"; then
-              if test -f "$dir/$libname.$acl_libext"; then
-                found_dir="$dir"
-                found_a="$dir/$libname.$acl_libext"
-              fi
-            fi
-            if test "X$found_dir" != "X"; then
-              if test -f "$dir/$libname.la"; then
-                found_la="$dir/$libname.la"
-              fi
-            fi
+            done
           fi
           if test "X$found_dir" = "X"; then
             for x in $LDFLAGS $LTLIB[]NAME; do
@@ -321,7 +335,7 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
                   dir=`echo "X$x" | sed -e 's/^X-L//'`
                   dnl First look for a shared library.
                   if test -n "$acl_shlibext"; then
-                    if test -f "$dir/$libname$shrext"; then
+                    if test -f "$dir/$libname$shrext" && acl_is_expected_elfclass < "$dir/$libname$shrext"; then
                       found_dir="$dir"
                       found_so="$dir/$libname$shrext"
                     else
@@ -331,14 +345,14 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
                               | sed -e "s,^$libname$shrext\\\\.,," \
                               | sort -t '.' -n -r -k1,1 -k2,2 -k3,3 -k4,4 -k5,5 \
                               | sed 1q ) 2>/dev/null`
-                        if test -n "$ver" && test -f "$dir/$libname$shrext.$ver"; then
+                        if test -n "$ver" && test -f "$dir/$libname$shrext.$ver" && acl_is_expected_elfclass < "$dir/$libname$shrext.$ver"; then
                           found_dir="$dir"
                           found_so="$dir/$libname$shrext.$ver"
                         fi
                       else
                         eval library_names=\"$acl_library_names_spec\"
                         for f in $library_names; do
-                          if test -f "$dir/$f"; then
+                          if test -f "$dir/$f" && acl_is_expected_elfclass < "$dir/$f"; then
                             found_dir="$dir"
                             found_so="$dir/$f"
                             break
@@ -349,7 +363,7 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
                   fi
                   dnl Then look for a static library.
                   if test "X$found_dir" = "X"; then
-                    if test -f "$dir/$libname.$acl_libext"; then
+                    if test -f "$dir/$libname.$acl_libext" && ${AR-ar} -p "$dir/$libname.$acl_libext" | acl_is_expected_elfclass; then
                       found_dir="$dir"
                       found_a="$dir/$libname.$acl_libext"
                     fi
@@ -375,7 +389,8 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
               dnl standard /usr/lib.
               if test "$enable_rpath" = no \
                  || test "X$found_dir" = "X/usr/$acl_libdirstem" \
-                 || test "X$found_dir" = "X/usr/$acl_libdirstem2"; then
+                 || test "X$found_dir" = "X/usr/$acl_libdirstem2" \
+                 || test "X$found_dir" = "X/usr/$acl_libdirstem3"; then
                 dnl No hardcoding is needed.
                 LIB[]NAME="${LIB[]NAME}${LIB[]NAME:+ }$found_so"
               else
@@ -475,6 +490,13 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
                 fi
                 additional_includedir="$basedir/include"
                 ;;
+              */$acl_libdirstem3 | */$acl_libdirstem3/)
+                basedir=`echo "X$found_dir" | sed -e 's,^X,,' -e "s,/$acl_libdirstem3/"'*$,,'`
+                if test "$name" = '$1'; then
+                  LIB[]NAME[]_PREFIX="$basedir"
+                fi
+                additional_includedir="$basedir/include"
+                ;;
             esac
             if test "X$additional_includedir" != "X"; then
               dnl Potentially add $additional_includedir to $INCNAME.
@@ -525,19 +547,21 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
               for dep in $dependency_libs; do
                 case "$dep" in
                   -L*)
-                    additional_libdir=`echo "X$dep" | sed -e 's/^X-L//'`
-                    dnl Potentially add $additional_libdir to $LIBNAME and $LTLIBNAME.
+                    dependency_libdir=`echo "X$dep" | sed -e 's/^X-L//'`
+                    dnl Potentially add $dependency_libdir to $LIBNAME and $LTLIBNAME.
                     dnl But don't add it
                     dnl   1. if it's the standard /usr/lib,
                     dnl   2. if it's /usr/local/lib and we are using GCC on Linux,
                     dnl   3. if it's already present in $LDFLAGS or the already
                     dnl      constructed $LIBNAME,
                     dnl   4. if it doesn't exist as a directory.
-                    if test "X$additional_libdir" != "X/usr/$acl_libdirstem" \
-                       && test "X$additional_libdir" != "X/usr/$acl_libdirstem2"; then
+                    if test "X$dependency_libdir" != "X/usr/$acl_libdirstem" \
+                       && test "X$dependency_libdir" != "X/usr/$acl_libdirstem2" \
+                       && test "X$dependency_libdir" != "X/usr/$acl_libdirstem3"; then
                       haveit=
-                      if test "X$additional_libdir" = "X/usr/local/$acl_libdirstem" \
-                         || test "X$additional_libdir" = "X/usr/local/$acl_libdirstem2"; then
+                      if test "X$dependency_libdir" = "X/usr/local/$acl_libdirstem" \
+                         || test "X$dependency_libdir" = "X/usr/local/$acl_libdirstem2" \
+                         || test "X$dependency_libdir" = "X/usr/local/$acl_libdirstem3"; then
                         if test -n "$GCC"; then
                           case $host_os in
                             linux* | gnu* | k*bsd*-gnu) haveit=yes;;
@@ -548,29 +572,29 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
                         haveit=
                         for x in $LDFLAGS $LIB[]NAME; do
                           AC_LIB_WITH_FINAL_PREFIX([eval x=\"$x\"])
-                          if test "X$x" = "X-L$additional_libdir"; then
+                          if test "X$x" = "X-L$dependency_libdir"; then
                             haveit=yes
                             break
                           fi
                         done
                         if test -z "$haveit"; then
-                          if test -d "$additional_libdir"; then
-                            dnl Really add $additional_libdir to $LIBNAME.
-                            LIB[]NAME="${LIB[]NAME}${LIB[]NAME:+ }-L$additional_libdir"
+                          if test -d "$dependency_libdir"; then
+                            dnl Really add $dependency_libdir to $LIBNAME.
+                            LIB[]NAME="${LIB[]NAME}${LIB[]NAME:+ }-L$dependency_libdir"
                           fi
                         fi
                         haveit=
                         for x in $LDFLAGS $LTLIB[]NAME; do
                           AC_LIB_WITH_FINAL_PREFIX([eval x=\"$x\"])
-                          if test "X$x" = "X-L$additional_libdir"; then
+                          if test "X$x" = "X-L$dependency_libdir"; then
                             haveit=yes
                             break
                           fi
                         done
                         if test -z "$haveit"; then
-                          if test -d "$additional_libdir"; then
-                            dnl Really add $additional_libdir to $LTLIBNAME.
-                            LTLIB[]NAME="${LTLIB[]NAME}${LTLIB[]NAME:+ }-L$additional_libdir"
+                          if test -d "$dependency_libdir"; then
+                            dnl Really add $dependency_libdir to $LTLIBNAME.
+                            LTLIB[]NAME="${LTLIB[]NAME}${LTLIB[]NAME:+ }-L$dependency_libdir"
                           fi
                         fi
                       fi
@@ -607,7 +631,20 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
                     ;;
                   -l*)
                     dnl Handle this in the next round.
-                    names_next_round="$names_next_round "`echo "X$dep" | sed -e 's/^X-l//'`
+                    dnl But on GNU systems, ignore -lc options, because
+                    dnl   - linking with libc is the default anyway,
+                    dnl   - linking with libc.a may produce an error
+                    dnl     "/usr/bin/ld: dynamic STT_GNU_IFUNC symbol `strcmp' with pointer equality in `/usr/lib/libc.a(strcmp.o)' can not be used when making an executable; recompile with -fPIE and relink with -pie"
+                    dnl     or may produce an executable that always crashes, see
+                    dnl     <https://lists.gnu.org/archive/html/grep-devel/2020-09/msg00052.html>.
+                    dep=`echo "X$dep" | sed -e 's/^X-l//'`
+                    if test "X$dep" != Xc \
+                       || case $host_os in
+                            linux* | gnu* | k*bsd*-gnu) false ;;
+                            *)                          true ;;
+                          esac; then
+                      names_next_round="$names_next_round $dep"
+                    fi
                     ;;
                   *.la)
                     dnl Handle this in the next round. Throw away the .la's
@@ -718,7 +755,8 @@ AC_DEFUN([AC_LIB_LINKFLAGS_FROM_LIBS],
           dir="$next"
           dnl No need to hardcode the standard /usr/lib.
           if test "X$dir" != "X/usr/$acl_libdirstem" \
-             && test "X$dir" != "X/usr/$acl_libdirstem2"; then
+             && test "X$dir" != "X/usr/$acl_libdirstem2" \
+             && test "X$dir" != "X/usr/$acl_libdirstem3"; then
             rpathdirs="$rpathdirs $dir"
           fi
           next=
@@ -728,7 +766,8 @@ AC_DEFUN([AC_LIB_LINKFLAGS_FROM_LIBS],
             -L*) dir=`echo "X$opt" | sed -e 's,^X-L,,'`
                  dnl No need to hardcode the standard /usr/lib.
                  if test "X$dir" != "X/usr/$acl_libdirstem" \
-                    && test "X$dir" != "X/usr/$acl_libdirstem2"; then
+                    && test "X$dir" != "X/usr/$acl_libdirstem2" \
+                    && test "X$dir" != "X/usr/$acl_libdirstem3"; then
                    rpathdirs="$rpathdirs $dir"
                  fi
                  next= ;;
index 8adb17bb9167df0d9efa87e3da6e5bec47033389..3c94db0acbd28bcca747d212e991561b0bf98186 100644 (file)
@@ -1,5 +1,5 @@
-# lib-prefix.m4 serial 14
-dnl Copyright (C) 2001-2005, 2008-2019 Free Software Foundation, Inc.
+# lib-prefix.m4 serial 19
+dnl Copyright (C) 2001-2005, 2008-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -147,21 +147,24 @@ AC_DEFUN([AC_LIB_WITH_FINAL_PREFIX],
 ])
 
 dnl AC_LIB_PREPARE_MULTILIB creates
-dnl - a variable acl_libdirstem, containing the basename of the libdir, either
-dnl   "lib" or "lib64" or "lib/64",
-dnl - a variable acl_libdirstem2, as a secondary possible value for
-dnl   acl_libdirstem, either the same as acl_libdirstem or "lib/sparcv9" or
-dnl   "lib/amd64".
+dnl - a function acl_is_expected_elfclass, that tests whether standard input
+dn;   has a 32-bit or 64-bit ELF header, depending on the host CPU ABI,
+dnl - 3 variables acl_libdirstem, acl_libdirstem2, acl_libdirstem3, containing
+dnl   the basename of the libdir to try in turn, either "lib" or "lib64" or
+dnl   "lib/64" or "lib32" or "lib/sparcv9" or "lib/amd64" or similar.
 AC_DEFUN([AC_LIB_PREPARE_MULTILIB],
 [
-  dnl There is no formal standard regarding lib and lib64.
-  dnl On glibc systems, the current practice is that on a system supporting
+  dnl There is no formal standard regarding lib, lib32, and lib64.
+  dnl On most glibc systems, the current practice is that on a system supporting
   dnl 32-bit and 64-bit instruction sets or ABIs, 64-bit libraries go under
-  dnl $prefix/lib64 and 32-bit libraries go under $prefix/lib. We determine
-  dnl the compiler's default mode by looking at the compiler's library search
-  dnl path. If at least one of its elements ends in /lib64 or points to a
-  dnl directory whose absolute pathname ends in /lib64, we assume a 64-bit ABI.
-  dnl Otherwise we use the default, namely "lib".
+  dnl $prefix/lib64 and 32-bit libraries go under $prefix/lib. However, on
+  dnl Arch Linux based distributions, it's the opposite: 32-bit libraries go
+  dnl under $prefix/lib32 and 64-bit libraries go under $prefix/lib.
+  dnl We determine the compiler's default mode by looking at the compiler's
+  dnl library search path. If at least one of its elements ends in /lib64 or
+  dnl points to a directory whose absolute pathname ends in /lib64, we use that
+  dnl for 64-bit ABIs. Similarly for 32-bit ABIs. Otherwise we use the default,
+  dnl namely "lib".
   dnl On Solaris systems, the current practice is that on a system supporting
   dnl 32-bit and 64-bit instruction sets or ABIs, 64-bit libraries go under
   dnl $prefix/lib/64 (which is a symlink to either $prefix/lib/sparcv9 or
@@ -169,27 +172,75 @@ AC_DEFUN([AC_LIB_PREPARE_MULTILIB],
   AC_REQUIRE([AC_CANONICAL_HOST])
   AC_REQUIRE([gl_HOST_CPU_C_ABI_32BIT])
 
-  case "$host_os" in
-    solaris*)
-      AC_CACHE_CHECK([for 64-bit host], [gl_cv_solaris_64bit],
-        [AC_COMPILE_IFELSE(
-           [AC_LANG_SOURCE(
-              [[#ifdef _LP64
-                 int ok;
-                #else
-                 error fail
-                #endif
-              ]])],
-           [gl_cv_solaris_64bit=yes],
-           [gl_cv_solaris_64bit=no])
-        ]);;
-  esac
+  AC_CACHE_CHECK([for ELF binary format], [gl_cv_elf],
+    [AC_EGREP_CPP([Extensible Linking Format],
+       [#ifdef __ELF__
+        Extensible Linking Format
+        #endif
+       ],
+       [gl_cv_elf=yes],
+       [gl_cv_elf=no])
+    ])
+  if test $gl_cv_elf = yes; then
+    # Extract the ELF class of a file (5th byte) in decimal.
+    # Cf. https://en.wikipedia.org/wiki/Executable_and_Linkable_Format#File_header
+    if od -A x < /dev/null >/dev/null 2>/dev/null; then
+      # Use POSIX od.
+      func_elfclass ()
+      {
+        od -A n -t d1 -j 4 -N 1
+      }
+    else
+      # Use BSD hexdump.
+      func_elfclass ()
+      {
+        dd bs=1 count=1 skip=4 2>/dev/null | hexdump -e '1/1 "%3d "'
+        echo
+      }
+    fi
+    # Use 'expr', not 'test', to compare the values of func_elfclass, because on
+    # Solaris 11 OpenIndiana and Solaris 11 OmniOS, the result is 001 or 002,
+    # not 1 or 2.
+changequote(,)dnl
+    case $HOST_CPU_C_ABI_32BIT in
+      yes)
+        # 32-bit ABI.
+        acl_is_expected_elfclass ()
+        {
+          expr "`func_elfclass | sed -e 's/[   ]//g'`" = 1 > /dev/null
+        }
+        ;;
+      no)
+        # 64-bit ABI.
+        acl_is_expected_elfclass ()
+        {
+          expr "`func_elfclass | sed -e 's/[   ]//g'`" = 2 > /dev/null
+        }
+        ;;
+      *)
+        # Unknown.
+        acl_is_expected_elfclass ()
+        {
+          :
+        }
+        ;;
+    esac
+changequote([,])dnl
+  else
+    acl_is_expected_elfclass ()
+    {
+      :
+    }
+  fi
 
   dnl Allow the user to override the result by setting acl_cv_libdirstems.
   AC_CACHE_CHECK([for the common suffixes of directories in the library search path],
     [acl_cv_libdirstems],
-    [acl_libdirstem=lib
+    [dnl Try 'lib' first, because that's the default for libdir in GNU, see
+     dnl <https://www.gnu.org/prep/standards/html_node/Directory-Variables.html>.
+     acl_libdirstem=lib
      acl_libdirstem2=
+     acl_libdirstem3=
      case "$host_os" in
        solaris*)
          dnl See Solaris 10 Software Developer Collection > Solaris 64-bit Developer's Guide > The Development Environment
@@ -197,53 +248,76 @@ AC_DEFUN([AC_LIB_PREPARE_MULTILIB],
          dnl "Portable Makefiles should refer to any library directories using the 64 symbolic link."
          dnl But we want to recognize the sparcv9 or amd64 subdirectory also if the
          dnl symlink is missing, so we set acl_libdirstem2 too.
-         if test $gl_cv_solaris_64bit = yes; then
-           acl_libdirstem=lib/64
+         if test $HOST_CPU_C_ABI_32BIT = no; then
+           acl_libdirstem2=lib/64
            case "$host_cpu" in
-             sparc*)        acl_libdirstem2=lib/sparcv9 ;;
-             i*86 | x86_64) acl_libdirstem2=lib/amd64 ;;
+             sparc*)        acl_libdirstem3=lib/sparcv9 ;;
+             i*86 | x86_64) acl_libdirstem3=lib/amd64 ;;
            esac
          fi
          ;;
        *)
          dnl If $CC generates code for a 32-bit ABI, the libraries are
-         dnl surely under $prefix/lib, not $prefix/lib64.
-         if test "$HOST_CPU_C_ABI_32BIT" != yes; then
-           dnl The result is a property of the system. However, non-system
-           dnl compilers sometimes have odd library search paths. Therefore
-           dnl prefer asking /usr/bin/gcc, if available, rather than $CC.
-           searchpath=`(if test -f /usr/bin/gcc \
-                           && LC_ALL=C /usr/bin/gcc -print-search-dirs >/dev/null 2>/dev/null; then \
-                          LC_ALL=C /usr/bin/gcc -print-search-dirs; \
-                        else \
-                          LC_ALL=C $CC -print-search-dirs; \
-                        fi) 2>/dev/null \
-                       | sed -n -e 's,^libraries: ,,p' | sed -e 's,^=,,'`
-           if test -n "$searchpath"; then
-             acl_save_IFS="${IFS=      }"; IFS=":"
-             for searchdir in $searchpath; do
-               if test -d "$searchdir"; then
-                 case "$searchdir" in
-                   */lib64/ | */lib64 ) acl_libdirstem=lib64 ;;
-                   */../ | */.. )
-                     # Better ignore directories of this form. They are misleading.
-                     ;;
-                   *) searchdir=`cd "$searchdir" && pwd`
-                      case "$searchdir" in
-                        */lib64 ) acl_libdirstem=lib64 ;;
-                      esac ;;
-                 esac
-               fi
-             done
-             IFS="$acl_save_IFS"
+         dnl surely under $prefix/lib or $prefix/lib32, not $prefix/lib64.
+         dnl Similarly, if $CC generates code for a 64-bit ABI, the libraries
+         dnl are surely under $prefix/lib or $prefix/lib64, not $prefix/lib32.
+         dnl Find the compiler's search path. However, non-system compilers
+         dnl sometimes have odd library search paths. But we can't simply invoke
+         dnl '/usr/bin/gcc -print-search-dirs' because that would not take into
+         dnl account the -m32/-m31 or -m64 options from the $CC or $CFLAGS.
+         searchpath=`(LC_ALL=C $CC $CPPFLAGS $CFLAGS -print-search-dirs) 2>/dev/null \
+                     | sed -n -e 's,^libraries: ,,p' | sed -e 's,^=,,'`
+         if test $HOST_CPU_C_ABI_32BIT != no; then
+           # 32-bit or unknown ABI.
+           if test -d /usr/lib32; then
+             acl_libdirstem2=lib32
+           fi
+         fi
+         if test $HOST_CPU_C_ABI_32BIT != yes; then
+           # 64-bit or unknown ABI.
+           if test -d /usr/lib64; then
+             acl_libdirstem3=lib64
+           fi
+         fi
+         if test -n "$searchpath"; then
+           acl_save_IFS="${IFS=        }"; IFS=":"
+           for searchdir in $searchpath; do
+             if test -d "$searchdir"; then
+               case "$searchdir" in
+                 */lib32/ | */lib32 ) acl_libdirstem2=lib32 ;;
+                 */lib64/ | */lib64 ) acl_libdirstem3=lib64 ;;
+                 */../ | */.. )
+                   # Better ignore directories of this form. They are misleading.
+                   ;;
+                 *) searchdir=`cd "$searchdir" && pwd`
+                    case "$searchdir" in
+                      */lib32 ) acl_libdirstem2=lib32 ;;
+                      */lib64 ) acl_libdirstem3=lib64 ;;
+                    esac ;;
+               esac
+             fi
+           done
+           IFS="$acl_save_IFS"
+           if test $HOST_CPU_C_ABI_32BIT = yes; then
+             # 32-bit ABI.
+             acl_libdirstem3=
+           fi
+           if test $HOST_CPU_C_ABI_32BIT = no; then
+             # 64-bit ABI.
+             acl_libdirstem2=
            fi
          fi
          ;;
      esac
      test -n "$acl_libdirstem2" || acl_libdirstem2="$acl_libdirstem"
-     acl_cv_libdirstems="$acl_libdirstem,$acl_libdirstem2"
+     test -n "$acl_libdirstem3" || acl_libdirstem3="$acl_libdirstem"
+     acl_cv_libdirstems="$acl_libdirstem,$acl_libdirstem2,$acl_libdirstem3"
     ])
-  # Decompose acl_cv_libdirstems into acl_libdirstem and acl_libdirstem2.
+  dnl Decompose acl_cv_libdirstems into acl_libdirstem, acl_libdirstem2, and
+  dnl acl_libdirstem3.
+changequote(,)dnl
   acl_libdirstem=`echo "$acl_cv_libdirstems" | sed -e 's/,.*//'`
-  acl_libdirstem2=`echo "$acl_cv_libdirstems" | sed -e '/,/s/.*,//'`
+  acl_libdirstem2=`echo "$acl_cv_libdirstems" | sed -e 's/^[^,]*,//' -e 's/,.*//'`
+  acl_libdirstem3=`echo "$acl_cv_libdirstems" | sed -e 's/^[^,]*,[^,]*,//' -e 's/,.*//'`
+changequote([,])dnl
 ])