diff --git a/m4/gpg-error.m4 b/m4/gpg-error.m4
index 0964a26..a9d572f 100644
--- a/m4/gpg-error.m4
+++ b/m4/gpg-error.m4
@@ -1,155 +1,188 @@
 # gpg-error.m4 - autoconf macro to detect libgpg-error.
 # Copyright (C) 2002, 2003, 2004, 2011, 2014, 2018 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: 2018-10-29
+# Last-changed: 2018-11-02
 
 
 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 $PATH.  If the used
 dnl config script does not match the host specification the script
 dnl is added to the gpg_config_script_warn variable.
 dnl
 AC_DEFUN([AM_PATH_GPG_ERROR],
 [ AC_REQUIRE([AC_CANONICAL_HOST])
   gpg_error_config_prefix=""
   dnl --with-libgpg-error-prefix=PFX is the preferred name for this option,
   dnl since that is consistent with how our three siblings use the directory/
   dnl package name in --with-$dir_name-prefix=PFX.
   AC_ARG_WITH(libgpg-error-prefix,
               AC_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)
   min_gpg_error_version=ifelse([$1], ,1.33,$1)
   ok=no
 
-  use_gpgrt_config=""
-  if test "$GPG_ERROR_CONFIG" = "no"; then
+  if test "$prefix" = NONE ; then
+    prefix_option_expanded=/usr/local
+  else
+    prefix_option_expanded="$prefix"
+  fi
+  if test "$exec_prefix" = NONE ; then
+    exec_prefix_option_expanded=$prefix_option_expanded
+  else
+    exec_prefix_option_expanded=$(prefix=$prefix_option_expanded eval echo $exec_prefix)
+  fi
+  libdir_option_expanded=$(prefix=$prefix_option_expanded exec_prefix=$exec_prefix_option_expanded eval echo $libdir)
+
+  if test -f $libdir_option_expanded/pkgconfig/gpg-error.pc; then
+    gpgrt_libdir=$libdir_option_expanded
+  else
+    if crt1_path=$(${CC:-cc} -print-file-name=crt1.o 2>/dev/null); then
+      if possible_libdir=$(cd ${crt1_path%/*} && pwd 2>/dev/null); then
+        if test -f $possible_libdir/pkgconfig/gpg-error.pc; then
+          gpgrt_libdir=$possible_libdir
+        fi
+      fi
+    fi
+  fi
+
+  if test "$GPG_ERROR_CONFIG" = "no" -a -n "$gpgrt_libdir"; then
     AC_PATH_PROG(GPGRT_CONFIG, gpgrt-config, no)
-    if test "$GPGRT_CONFIG" != "no"; then
-      GPGRT_CONFIG="$GPGRT_CONFIG --prefix=$prefix --exec-prefix=$exec_prefix --libdir=$libdir"
+    if test "$GPGRT_CONFIG" = "no"; then
+      unset GPGRT_CONFIG
+    else
+      GPGRT_CONFIG="$GPGRT_CONFIG --libdir=$gpgrt_libdir"
       if $GPGRT_CONFIG gpg-error >/dev/null 2>&1; then
         GPG_ERROR_CONFIG="$GPGRT_CONFIG gpg-error"
-        use_gpgrt_config=yes
+        AC_MSG_NOTICE([Use gpgrt-config with $gpgrt_libdir as gpg-error-config])
         gpg_error_config_version=`$GPG_ERROR_CONFIG --modversion`
+      else
+        unset GPGRT_CONFIG
       fi
     fi
   else
     gpg_error_config_version=`$GPG_ERROR_CONFIG --version`
   fi
   if test "$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
-    if test -z "$GPGRT_CONFIG"; then
+    if test -z "$GPGRT_CONFIG" -a -n "$gpgrt_libdir"; then
       if test "$major" -gt 1 -o "$major" -eq 1 -a "$minor" -ge 33; then
         AC_PATH_PROG(GPGRT_CONFIG, gpgrt-config, no)
-        if test "$GPGRT_CONFIG" != "no"; then
-          GPGRT_CONFIG="$GPGRT_CONFIG --prefix=$prefix --exec-prefix=$exec_prefix --libdir=$libdir"
-          GPG_ERROR_CONFIG="$GPGRT_CONFIG gpg-error"
-          use_gpgrt_config=yes
+        if test "$GPGRT_CONFIG" = "no"; then
+          unset GPGRT_CONFIG
+        else
+          GPGRT_CONFIG="$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])
+          else
+            unset GPGRT_CONFIG
+          fi
         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=`$GPG_ERROR_CONFIG --libs`
-    if test -z "$use_gpgrt_config"; then
+    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], , :, [$2])
-    if test -z "$use_gpgrt_config"; then
+    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)
 ])
diff --git a/src/ksba.m4 b/src/ksba.m4
index ee4b962..ad8de4f 100644
--- a/src/ksba.m4
+++ b/src/ksba.m4
@@ -1,154 +1,155 @@
 # ksba.m4 - autoconf macro to detect ksba
 #       Copyright (C) 2002, 2018 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.
 
 
 dnl AM_PATH_KSBA([MINIMUM-VERSION,
 dnl              [ACTION-IF-FOUND [, ACTION-IF-NOT-FOUND ]]])
 dnl Test for libksba and define KSBA_CFLAGS and KSBA_LIBS
 dnl MINIMUN-VERSION is a string with the version number optionalliy prefixed
 dnl with the API version to also check the API compatibility. Example:
 dnl a MINIMUN-VERSION of 1:1.0.7 won't pass the test unless the installed
 dnl version of libksba is at least 1.0.7 *and* the API number is 1.  Using
 dnl this features allows to prevent build against newer versions of libksba
 dnl with a changed API.
 dnl
 AC_DEFUN([AM_PATH_KSBA],
 [ AC_REQUIRE([AC_CANONICAL_HOST])
   dnl --with-libksba-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-$dir_name-prefix=PFX.
   AC_ARG_WITH(libksba-prefix,
               AC_HELP_STRING([--with-libksba-prefix=PFX],
                              [prefix where KSBA is installed (optional)]),
      ksba_config_prefix="$withval", ksba_config_prefix="")
 
   dnl Accept --with-ksba-prefix and make it work the same as
   dnl --with-libksba-prefix above, for backwards compatibility,
   dnl but do not document this old, inconsistently-named option.
   AC_ARG_WITH(ksba-prefix,,
      ksba_config_prefix="$withval", ksba_config_prefix="")
 
   if test x$ksba_config_prefix != x ; then
     if test x${KSBA_CONFIG+set} != xset ; then
       KSBA_CONFIG=$ksba_config_prefix/bin/ksba-config
     fi
   fi
 
   use_gpgrt_config=""
   if test x"$KSBA_CONFIG" = x -a x"$GPGRT_CONFIG" != x -a "$GPGRT_CONFIG" != "no"; then
     if $GPGRT_CONFIG ksba --exists; then
       KSBA_CONFIG="$GPGRT_CONFIG ksba"
+      AC_MSG_NOTICE([Use gpgrt-config as ksba-config])
       use_gpgrt_config=yes
     fi
   fi
   if test -z "$use_gpgrt_config"; then
     AC_PATH_PROG(KSBA_CONFIG, ksba-config, no)
   fi
 
   tmp=ifelse([$1], ,1:1.0.0,$1)
   if echo "$tmp" | grep ':' >/dev/null 2>/dev/null ; then
      req_ksba_api=`echo "$tmp"     | sed 's/\(.*\):\(.*\)/\1/'`
      min_ksba_version=`echo "$tmp" | sed 's/\(.*\):\(.*\)/\2/'`
   else
      req_ksba_api=0
      min_ksba_version="$tmp"
   fi
 
   AC_MSG_CHECKING(for KSBA - version >= $min_ksba_version)
   ok=no
   if test "$KSBA_CONFIG" != "no" ; then
     req_major=`echo $min_ksba_version | \
                sed 's/\([[0-9]]*\)\.\([[0-9]]*\)\.\([[0-9]]*\)/\1/'`
     req_minor=`echo $min_ksba_version | \
                sed 's/\([[0-9]]*\)\.\([[0-9]]*\)\.\([[0-9]]*\)/\2/'`
     req_micro=`echo $min_ksba_version | \
                sed 's/\([[0-9]]*\)\.\([[0-9]]*\)\.\([[0-9]]*\)/\3/'`
     if test -z "$use_gpgrt_config"; then
       ksba_config_version=`$KSBA_CONFIG --version`
     else
       ksba_config_version=`$KSBA_CONFIG --modversion`
     fi
     major=`echo $ksba_config_version | \
                sed 's/\([[0-9]]*\)\.\([[0-9]]*\)\.\([[0-9]]*\).*/\1/'`
     minor=`echo $ksba_config_version | \
                sed 's/\([[0-9]]*\)\.\([[0-9]]*\)\.\([[0-9]]*\).*/\2/'`
     micro=`echo $ksba_config_version | \
                sed 's/\([[0-9]]*\)\.\([[0-9]]*\)\.\([[0-9]]*\).*/\3/'`
     if test "$major" -gt "$req_major"; then
         ok=yes
     else
         if test "$major" -eq "$req_major"; then
             if test "$minor" -gt "$req_minor"; then
                ok=yes
             else
                if test "$minor" -eq "$req_minor"; then
                    if test "$micro" -ge "$req_micro"; then
                      ok=yes
                    fi
                fi
             fi
         fi
     fi
   fi
   if test $ok = yes; then
     AC_MSG_RESULT([yes ($ksba_config_version)])
   else
     AC_MSG_RESULT(no)
   fi
   if test $ok = yes; then
      # Even if we have a recent libksba, we should check that the
      # API is compatible.
      if test "$req_ksba_api" -gt 0 ; then
         if test -z "$use_gpgrt_config"; then
           tmp=`$KSBA_CONFIG --api-version 2>/dev/null || echo 0`
 	else
           tmp=`$KSBA_CONFIG --variable=api_version 2>/dev/null || echo 0`
 	fi
         if test "$tmp" -gt 0 ; then
            AC_MSG_CHECKING([KSBA API version])
            if test "$req_ksba_api" -eq "$tmp" ; then
              AC_MSG_RESULT(okay)
            else
              ok=no
              AC_MSG_RESULT([does not match.  want=$req_ksba_api got=$tmp.])
            fi
         fi
      fi
   fi
   if test $ok = yes; then
     KSBA_CFLAGS=`$KSBA_CONFIG --cflags`
     KSBA_LIBS=`$KSBA_CONFIG --libs`
     ifelse([$2], , :, [$2])
     if test -z "$use_gpgrt_config"; then
       libksba_config_host=`$KSBA_CONFIG --host 2>/dev/null || echo none`
     else
       libksba_config_host=`$KSBA_CONFIG --variable=host 2>/dev/null || echo none`
     fi
     if test x"$libksba_config_host" != xnone ; then
       if test x"$libksba_config_host" != x"$host" ; then
   AC_MSG_WARN([[
 ***
 *** The config script "$KSBA_CONFIG" was
 *** built for $libksba_config_host and thus may not match the
 *** used host $host.
 *** You may want to use the configure option --with-libksba-prefix
 *** to specify a matching config script.
 ***]])
       fi
     fi
   else
     KSBA_CFLAGS=""
     KSBA_LIBS=""
     ifelse([$3], , :, [$3])
   fi
   AC_SUBST(KSBA_CFLAGS)
   AC_SUBST(KSBA_LIBS)
 ])