diff --git a/m4/gpg-error.m4 b/m4/gpg-error.m4
index 7fa52b1..3ae3233 100644
--- a/m4/gpg-error.m4
+++ b/m4/gpg-error.m4
@@ -1,225 +1,234 @@
 # gpg-error.m4 - autoconf macro to detect libgpg-error.
-# Copyright (C) 2002, 2003, 2004, 2011, 2014, 2018, 2020, 2021, 2022
+# Copyright (C) 2002, 2003, 2004, 2011, 2014, 2018, 2020, 2021, 2022, 2024
 #               g10 Code GmbH
 #
 # This file is free software; as a special exception the author gives
 # unlimited permission to copy and/or distribute it, with or without
 # modifications, as long as this notice is preserved.
 #
 # This file is distributed in the hope that it will be useful, but
 # WITHOUT ANY WARRANTY, to the extent permitted by law; without even the
 # implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 #
-# Last-changed: 2023-04-01
+# Last-changed: 2024-06-13
 
 dnl
 dnl Find gpg-error-config, for backward compatibility
 dnl
 dnl _AM_PATH_POSSIBLE_GPG_ERROR_CONFIG
 AC_DEFUN([_AM_PATH_POSSIBLE_GPG_ERROR_CONFIG],[dnl
   gpg_error_config_prefix=""
   dnl --with-libgpg-error-prefix=PFX is the preferred name for this option,
   dnl since that is consistent with how our three siblings use the directory/
   dnl package name in --with-$dir_name-prefix=PFX.
   AC_ARG_WITH(libgpg-error-prefix,
               AS_HELP_STRING([--with-libgpg-error-prefix=PFX],
                              [prefix where GPG Error is installed (optional)]),
               [gpg_error_config_prefix="$withval"])
 
   dnl Accept --with-gpg-error-prefix and make it work the same as
   dnl --with-libgpg-error-prefix above, for backwards compatibility,
   dnl but do not document this old, inconsistently-named option.
   AC_ARG_WITH(gpg-error-prefix,,
               [gpg_error_config_prefix="$withval"])
 
   if test x"${GPG_ERROR_CONFIG}" = x ; then
      if test x"${gpg_error_config_prefix}" != x ; then
         GPG_ERROR_CONFIG="${gpg_error_config_prefix}/bin/gpg-error-config"
      else
        case "${SYSROOT}" in
          /*)
            if test -x "${SYSROOT}/bin/gpg-error-config" ; then
              GPG_ERROR_CONFIG="${SYSROOT}/bin/gpg-error-config"
            fi
            ;;
          '')
            ;;
           *)
            AC_MSG_WARN([Ignoring \$SYSROOT as it is not an absolute path.])
            ;;
        esac
      fi
   fi
 
   AC_PATH_PROG(GPG_ERROR_CONFIG, gpg-error-config, no)
 ])
 
 dnl
 dnl Find gpgrt-config, which uses .pc file
 dnl (minimum pkg-config functionality, supporting cross build)
 dnl
 dnl _AM_PATH_GPGRT_CONFIG
 AC_DEFUN([_AM_PATH_GPGRT_CONFIG],[dnl
   AC_PATH_PROG(GPGRT_CONFIG, gpgrt-config, no, [$prefix/bin:$PATH])
   if test "$GPGRT_CONFIG" != "no"; then
     # Determine gpgrt_libdir
     #
     # Get the prefix of gpgrt-config assuming it's something like:
     #   <PREFIX>/bin/gpgrt-config
     gpgrt_prefix=${GPGRT_CONFIG%/*/*}
     possible_libdir1=${gpgrt_prefix}/lib
     # Determine by using system libdir-format with CC, it's like:
     #   Normal style: /usr/lib
     #   GNU cross style: /usr/<triplet>/lib
     #   Debian style: /usr/lib/<multiarch-name>
     #   Fedora/openSUSE style: /usr/lib, /usr/lib32 or /usr/lib64
     # It is assumed that CC is specified to the one of host on cross build.
     if libdir_candidates=$(${CC:-cc} -print-search-dirs | \
           sed -n -e "/^libraries/{s/libraries: =//;s/:/\\
 /g;p;}"); then
       # From the output of -print-search-dirs, select valid pkgconfig dirs.
       libdir_candidates=$(for dir in $libdir_candidates; do
         if p=$(cd $dir 2>/dev/null && pwd); then
           test -d "$p/pkgconfig" && echo $p;
         fi
       done)
 
       for possible_libdir0 in $libdir_candidates; do
         # possible_libdir0:
         #   Fallback candidate, the one of system-installed (by $CC)
         #   (/usr/<triplet>/lib, /usr/lib/<multiarch-name> or /usr/lib32)
         # possible_libdir1:
         #   Another candidate, user-locally-installed
         #   (<gpgrt_prefix>/lib)
         # possible_libdir2
         #   Most preferred
         #   (<gpgrt_prefix>/<triplet>/lib,
         #    <gpgrt_prefix>/lib/<multiarch-name> or <gpgrt_prefix>/lib32)
         if test "${possible_libdir0##*/}" = "lib"; then
           possible_prefix0=${possible_libdir0%/lib}
           possible_prefix0_triplet=${possible_prefix0##*/}
           if test -z "$possible_prefix0_triplet"; then
             continue
           fi
           possible_libdir2=${gpgrt_prefix}/$possible_prefix0_triplet/lib
         else
           possible_prefix0=${possible_libdir0%%/lib*}
           possible_libdir2=${gpgrt_prefix}${possible_libdir0#$possible_prefix0}
         fi
         if test -f ${possible_libdir2}/pkgconfig/gpg-error.pc; then
           gpgrt_libdir=${possible_libdir2}
         elif test -f ${possible_libdir1}/pkgconfig/gpg-error.pc; then
           gpgrt_libdir=${possible_libdir1}
         elif test -f ${possible_libdir0}/pkgconfig/gpg-error.pc; then
           gpgrt_libdir=${possible_libdir0}
         fi
         if test -n "$gpgrt_libdir"; then break; fi
       done
     fi
     if test -z "$gpgrt_libdir"; then
       # No valid pkgconfig dir in any of the system directories, fallback
       gpgrt_libdir=${possible_libdir1}
     fi
   else
     unset GPGRT_CONFIG
   fi
 
   if test -n "$gpgrt_libdir"; then
+    # Add the --libdir option to GPGRT_CONFIG
     GPGRT_CONFIG="$GPGRT_CONFIG --libdir=$gpgrt_libdir"
-    if $GPGRT_CONFIG gpg-error >/dev/null 2>&1; then
-      GPG_ERROR_CONFIG="$GPGRT_CONFIG gpg-error"
-      AC_MSG_NOTICE([Use gpgrt-config with $gpgrt_libdir as gpg-error-config])
-      gpg_error_config_version=`$GPG_ERROR_CONFIG --modversion`
-    else
-      gpg_error_config_version=`$GPG_ERROR_CONFIG --version`
+    # Make sure if gpgrt-config really works, by testing config gpg-error
+    if ! $GPGRT_CONFIG gpg-error --exists; then
+      # If it doesn't work, clear the GPGRT_CONFIG variable.
       unset GPGRT_CONFIG
     fi
-  elif test "$GPG_ERROR_CONFIG" != "no"; then
-    gpg_error_config_version=`$GPG_ERROR_CONFIG --version`
+  else
+    # GPGRT_CONFIG found but no suitable dir for --libdir found.
+    # This is a failure.  Clear the GPGRT_CONFIG variable.
     unset GPGRT_CONFIG
   fi
 ])
 
 dnl AM_PATH_GPG_ERROR([MINIMUM-VERSION,
 dnl                   [ACTION-IF-FOUND [, ACTION-IF-NOT-FOUND ]]])
 dnl
 dnl Test for libgpg-error and define GPG_ERROR_CFLAGS, GPG_ERROR_LIBS,
 dnl GPG_ERROR_MT_CFLAGS, and GPG_ERROR_MT_LIBS.  The _MT_ variants are
 dnl used for programs requireing real multi thread support.
 dnl
 dnl If a prefix option is not used, the config script is first
 dnl searched in $SYSROOT/bin and then along $PATH.  If the used
 dnl config script does not match the host specification the script
 dnl is added to the gpg_config_script_warn variable.
 dnl
-AC_DEFUN([AM_PATH_GPG_ERROR],[dnl
-AC_REQUIRE([AC_CANONICAL_HOST])dnl
-AC_REQUIRE([_AM_PATH_POSSIBLE_GPG_ERROR_CONFIG])dnl
-AC_REQUIRE([_AM_PATH_GPGRT_CONFIG])dnl
+AC_DEFUN([AM_PATH_GPG_ERROR],
+[ AC_REQUIRE([AC_CANONICAL_HOST])dnl
+  AC_REQUIRE([_AM_PATH_POSSIBLE_GPG_ERROR_CONFIG])dnl
+  AC_REQUIRE([_AM_PATH_GPGRT_CONFIG])dnl
+  if test x"$GPGRT_CONFIG" != x -a "$GPGRT_CONFIG" != "no"; then
+    GPG_ERROR_CONFIG="$GPGRT_CONFIG gpg-error"
+    AC_MSG_NOTICE([Use gpgrt-config with $gpgrt_libdir as gpg-error-config])
+    gpg_error_config_version=`$GPG_ERROR_CONFIG --modversion`
+  elif test x"$GPG_ERROR_CONFIG" != x -a "$GPG_ERROR_CONFIG" != "no"; then
+    gpg_error_config_version=`$GPG_ERROR_CONFIG --version`
+  else
+    gpg_error_config_version="0.0"
+  fi
+
   min_gpg_error_version=ifelse([$1], ,1.33,$1)
   ok=no
   if test "$GPG_ERROR_CONFIG" != "no"; then
     req_major=`echo $min_gpg_error_version | \
                sed 's/\([[0-9]]*\)\.\([[0-9]]*\)/\1/'`
     req_minor=`echo $min_gpg_error_version | \
                sed 's/\([[0-9]]*\)\.\([[0-9]]*\)/\2/'`
     major=`echo $gpg_error_config_version | \
                sed 's/\([[0-9]]*\)\.\([[0-9]]*\).*/\1/'`
     minor=`echo $gpg_error_config_version | \
                sed 's/\([[0-9]]*\)\.\([[0-9]]*\).*/\2/'`
     if test "$major" -gt "$req_major"; then
         ok=yes
     else
         if test "$major" -eq "$req_major"; then
             if test "$minor" -ge "$req_minor"; then
                ok=yes
             fi
         fi
     fi
   fi
   AC_MSG_CHECKING(for GPG Error - version >= $min_gpg_error_version)
   if test $ok = yes; then
     GPG_ERROR_CFLAGS=`$GPG_ERROR_CONFIG --cflags`
     GPG_ERROR_LIBS=`$GPG_ERROR_CONFIG --libs`
     if test -z "$GPGRT_CONFIG"; then
       GPG_ERROR_MT_CFLAGS=`$GPG_ERROR_CONFIG --mt --cflags 2>/dev/null`
       GPG_ERROR_MT_LIBS=`$GPG_ERROR_CONFIG --mt --libs 2>/dev/null`
     else
       GPG_ERROR_MT_CFLAGS=`$GPG_ERROR_CONFIG --variable=mtcflags 2>/dev/null`
       GPG_ERROR_MT_CFLAGS="$GPG_ERROR_CFLAGS${GPG_ERROR_CFLAGS:+ }$GPG_ERROR_MT_CFLAGS"
       GPG_ERROR_MT_LIBS=`$GPG_ERROR_CONFIG --variable=mtlibs 2>/dev/null`
       GPG_ERROR_MT_LIBS="$GPG_ERROR_LIBS${GPG_ERROR_LIBS:+ }$GPG_ERROR_MT_LIBS"
     fi
     AC_MSG_RESULT([yes ($gpg_error_config_version)])
     ifelse([$2], , :, [$2])
     if test -z "$GPGRT_CONFIG"; then
       gpg_error_config_host=`$GPG_ERROR_CONFIG --host 2>/dev/null || echo none`
     else
       gpg_error_config_host=`$GPG_ERROR_CONFIG --variable=host 2>/dev/null || echo none`
     fi
     if test x"$gpg_error_config_host" != xnone ; then
       if test x"$gpg_error_config_host" != x"$host" ; then
   AC_MSG_WARN([[
 ***
 *** The config script "$GPG_ERROR_CONFIG" was
 *** built for $gpg_error_config_host and thus may not match the
 *** used host $host.
 *** You may want to use the configure option --with-libgpg-error-prefix
 *** to specify a matching config script or use \$SYSROOT.
 ***]])
         gpg_config_script_warn="$gpg_config_script_warn libgpg-error"
       fi
     fi
   else
     GPG_ERROR_CFLAGS=""
     GPG_ERROR_LIBS=""
     GPG_ERROR_MT_CFLAGS=""
     GPG_ERROR_MT_LIBS=""
     AC_MSG_RESULT(no)
     ifelse([$3], , :, [$3])
   fi
   AC_SUBST(GPG_ERROR_CFLAGS)
   AC_SUBST(GPG_ERROR_LIBS)
   AC_SUBST(GPG_ERROR_MT_CFLAGS)
   AC_SUBST(GPG_ERROR_MT_LIBS)
 ])