havelib: Make libdirstems processing more flexible.

* m4/lib-prefix.m4 (AC_LIB_PREPARE_MULTILIB): Set 3 libdirstem
variables: Consider 'lib' always, also on Solaris. Look for lib32 in
addition to lib64. Don't invoke /usr/bin/gcc (reverting the second
patch from 2017-02-19).
* m4/lib-link.m4 (AC_LIB_LINKFLAGS_BODY): Consider up to 3 additional
libdirs, even when the first one exists as a directory.

3 files changed, 159 insertions, 96 deletions

diff --git a/ChangeLog b/ChangeLog
index 3b5fcb1690..2c5b818c65 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,15 @@
 2019-11-17  Bruno Haible  <bruno@clisp.org>
 
+	havelib: Make libdirstems processing more flexible.
+	* m4/lib-prefix.m4 (AC_LIB_PREPARE_MULTILIB): Set 3 libdirstem
+	variables: Consider 'lib' always, also on Solaris. Look for lib32 in
+	addition to lib64. Don't invoke /usr/bin/gcc (reverting the second
+	patch from 2017-02-19).
+	* m4/lib-link.m4 (AC_LIB_LINKFLAGS_BODY): Consider up to 3 additional
+	libdirs, even when the first one exists as a directory.
+
+2019-11-17  Bruno Haible  <bruno@clisp.org>
+
 	havelib: Match the bitness when searching for libraries.
 	* m4/lib-prefix.m4 (AC_LIB_PREPARE_MULTILIB): Define a function
 	acl_is_expected_elfclass.
diff --git a/m4/lib-link.m4 b/m4/lib-link.m4
index 5efbbffe26..b9fa364856 100644
--- a/m4/lib-link.m4
+++ b/m4/lib-link.m4
@@ -1,4 +1,4 @@
-# lib-link.m4 serial 30
+# lib-link.m4 serial 31
 dnl Copyright (C) 2001-2019 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -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" && 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.$ver"
+            for additional_libdir_variable in additional_libdir additional_libdir2 additional_libdir3; do
+              if test "X$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/$f" && acl_is_expected_elfclass < "$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" && ${AR-ar} -p "$dir/$libname.$acl_libext" | acl_is_expected_elfclass; 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 $LTLIB[]NAME; do
@@ -375,7 +389,8 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
               dnl standard /usr/lib.
               if test "$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.
@@ -534,10 +556,12 @@ AC_DEFUN([AC_LIB_LINKFLAGS_BODY],
                     dnl      constructed $LIBNAME,
                     dnl   4. if it doesn't exist as a directory.
                     if test "X$dependency_libdir" != "X/usr/$acl_libdirstem" \
-                       && test "X$dependency_libdir" != "X/usr/$acl_libdirstem2"; then
+                       && test "X$dependency_libdir" != "X/usr/$acl_libdirstem2" \
+                       && test "X$dependency_libdir" != "X/usr/$acl_libdirstem3"; then
                       haveit=
                       if test "X$dependency_libdir" = "X/usr/local/$acl_libdirstem" \
-                         || test "X$dependency_libdir" = "X/usr/local/$acl_libdirstem2"; then
+                         || test "X$dependency_libdir" = "X/usr/local/$acl_libdirstem2" \
+                         || test "X$dependency_libdir" = "X/usr/local/$acl_libdirstem3"; then
                         if test -n "$GCC"; then
                           case $host_os in
                             linux* | gnu* | k*bsd*-gnu) haveit=yes;;
@@ -718,7 +742,8 @@ AC_DEFUN([AC_LIB_LINKFLAGS_FROM_LIBS],
           dir="$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 $dir"
           fi
           next=
@@ -728,7 +753,8 @@ AC_DEFUN([AC_LIB_LINKFLAGS_FROM_LIBS],
             -L*) dir=`echo "X$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= ;;
diff --git a/m4/lib-prefix.m4 b/m4/lib-prefix.m4
index 976c1a7099..52ea5aef15 100644
--- a/m4/lib-prefix.m4
+++ b/m4/lib-prefix.m4
@@ -1,4 +1,4 @@
-# lib-prefix.m4 serial 16
+# lib-prefix.m4 serial 17
 dnl Copyright (C) 2001-2005, 2008-2019 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -149,21 +149,22 @@ AC_DEFUN([AC_LIB_WITH_FINAL_PREFIX],
 dnl AC_LIB_PREPARE_MULTILIB creates
 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 - 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 - 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 $prefix/lib/sparcv9 or
@@ -232,8 +233,11 @@ changequote([,])dnl
   dnl Allow the user to override the result by setting acl_cv_libdirstems.
   AC_CACHE_CHECK([for the common suffixes of directories in the library search path],
     [acl_cv_libdirstems],
-    [acl_libdirstem=lib
+    [dnl Try 'lib' first, because that's the default for libdir in GNU, see
+     dnl <https://www.gnu.org/prep/standards/html_node/Directory-Variables.html>.
+     acl_libdirstem=lib
      acl_libdirstem2=
+     acl_libdirstem3=
      case "$host_os" in
        solaris*)
          dnl See Solaris 10 Software Developer Collection > Solaris 64-bit Developer's Guide > The Development Environment
@@ -242,52 +246,75 @@ changequote([,])dnl
          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 $HOST_CPU_C_ABI_32BIT = no; then
-           acl_libdirstem=lib/64
+           acl_libdirstem2=lib/64
            case "$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
 ])