diff --git a/m4/ax_check_gnu_make.m4 b/m4/ax_check_gnu_make.m4
index 6762e9ed..4c761ea0 100644
--- a/m4/ax_check_gnu_make.m4
+++ b/m4/ax_check_gnu_make.m4
@@ -1,5 +1,5 @@
# ===========================================================================
-# http://www.gnu.org/software/autoconf-archive/ax_check_gnu_make.html
+# https://www.gnu.org/software/autoconf-archive/ax_check_gnu_make.html
# ===========================================================================
#
# SYNOPSIS
@@ -61,7 +61,7 @@
# and this notice are preserved. This file is offered as-is, without any
# warranty.
-#serial 8
+#serial 9
AC_DEFUN([AX_CHECK_GNU_MAKE],dnl
[AC_PROG_AWK
diff --git a/m4/ax_pthread.m4 b/m4/ax_pthread.m4
index fff77db6..5fbf9fe0 100644
--- a/m4/ax_pthread.m4
+++ b/m4/ax_pthread.m4
@@ -1,5 +1,5 @@
# ===========================================================================
-# http://www.gnu.org/software/autoconf-archive/ax_pthread.html
+# https://www.gnu.org/software/autoconf-archive/ax_pthread.html
# ===========================================================================
#
# SYNOPSIS
@@ -67,7 +67,7 @@
# Public License for more details.
#
# You should have received a copy of the GNU General Public License along
-# with this program. If not, see .
+# with this program. If not, see .
#
# As a special exception, the respective Autoconf Macro's copyright owner
# gives unlimited permission to copy, distribute and modify the configure
diff --git a/m4/pkg.m4 b/m4/pkg.m4
deleted file mode 100644
index c0a8d3d7..00000000
--- a/m4/pkg.m4
+++ /dev/null
@@ -1,214 +0,0 @@
-# pkg.m4 - Macros to locate and utilise pkg-config. -*- Autoconf -*-
-# serial 1 (pkg-config-0.24)
-#
-# Copyright © 2004 Scott James Remnant .
-#
-# 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
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful, but
-# WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 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, write to the Free Software
-# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
-#
-# As a special exception to the GNU General Public License, if you
-# distribute this file as part of a program that contains a
-# configuration script generated by Autoconf, you may include it under
-# the same distribution terms that you use for the rest of that program.
-
-# PKG_PROG_PKG_CONFIG([MIN-VERSION])
-# ----------------------------------
-AC_DEFUN([PKG_PROG_PKG_CONFIG],
-[m4_pattern_forbid([^_?PKG_[A-Z_]+$])
-m4_pattern_allow([^PKG_CONFIG(_(PATH|LIBDIR|SYSROOT_DIR|ALLOW_SYSTEM_(CFLAGS|LIBS)))?$])
-m4_pattern_allow([^PKG_CONFIG_(DISABLE_UNINSTALLED|TOP_BUILD_DIR|DEBUG_SPEW)$])
-AC_ARG_VAR([PKG_CONFIG], [path to pkg-config utility])
-AC_ARG_VAR([PKG_CONFIG_PATH], [directories to add to pkg-config's search path])
-AC_ARG_VAR([PKG_CONFIG_LIBDIR], [path overriding pkg-config's built-in search path])
-
-if test "x$ac_cv_env_PKG_CONFIG_set" != "xset"; then
- AC_PATH_TOOL([PKG_CONFIG], [pkg-config])
-fi
-if test -n "$PKG_CONFIG"; then
- _pkg_min_version=m4_default([$1], [0.9.0])
- AC_MSG_CHECKING([pkg-config is at least version $_pkg_min_version])
- if $PKG_CONFIG --atleast-pkgconfig-version $_pkg_min_version; then
- AC_MSG_RESULT([yes])
- else
- AC_MSG_RESULT([no])
- PKG_CONFIG=""
- fi
-fi[]dnl
-])# PKG_PROG_PKG_CONFIG
-
-# PKG_CHECK_EXISTS(MODULES, [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
-#
-# Check to see whether a particular set of modules exists. Similar
-# to PKG_CHECK_MODULES(), but does not set variables or print errors.
-#
-# Please remember that m4 expands AC_REQUIRE([PKG_PROG_PKG_CONFIG])
-# only at the first occurrence in configure.ac, so if the first place
-# it's called might be skipped (such as if it is within an "if", you
-# have to call PKG_CHECK_EXISTS manually
-# --------------------------------------------------------------
-AC_DEFUN([PKG_CHECK_EXISTS],
-[AC_REQUIRE([PKG_PROG_PKG_CONFIG])dnl
-if test -n "$PKG_CONFIG" && \
- AC_RUN_LOG([$PKG_CONFIG --exists --print-errors "$1"]); then
- m4_default([$2], [:])
-m4_ifvaln([$3], [else
- $3])dnl
-fi])
-
-# _PKG_CONFIG([VARIABLE], [COMMAND], [MODULES])
-# ---------------------------------------------
-m4_define([_PKG_CONFIG],
-[if test -n "$$1"; then
- pkg_cv_[]$1="$$1"
- elif test -n "$PKG_CONFIG"; then
- PKG_CHECK_EXISTS([$3],
- [pkg_cv_[]$1=`$PKG_CONFIG --[]$2 "$3" 2>/dev/null`
- test "x$?" != "x0" && pkg_failed=yes ],
- [pkg_failed=yes])
- else
- pkg_failed=untried
-fi[]dnl
-])# _PKG_CONFIG
-
-# _PKG_SHORT_ERRORS_SUPPORTED
-# -----------------------------
-AC_DEFUN([_PKG_SHORT_ERRORS_SUPPORTED],
-[AC_REQUIRE([PKG_PROG_PKG_CONFIG])
-if $PKG_CONFIG --atleast-pkgconfig-version 0.20; then
- _pkg_short_errors_supported=yes
-else
- _pkg_short_errors_supported=no
-fi[]dnl
-])# _PKG_SHORT_ERRORS_SUPPORTED
-
-
-# PKG_CHECK_MODULES(VARIABLE-PREFIX, MODULES, [ACTION-IF-FOUND],
-# [ACTION-IF-NOT-FOUND])
-#
-#
-# Note that if there is a possibility the first call to
-# PKG_CHECK_MODULES might not happen, you should be sure to include an
-# explicit call to PKG_PROG_PKG_CONFIG in your configure.ac
-#
-#
-# --------------------------------------------------------------
-AC_DEFUN([PKG_CHECK_MODULES],
-[AC_REQUIRE([PKG_PROG_PKG_CONFIG])dnl
-AC_ARG_VAR([$1][_CFLAGS], [C compiler flags for $1, overriding pkg-config])dnl
-AC_ARG_VAR([$1][_LIBS], [linker flags for $1, overriding pkg-config])dnl
-
-pkg_failed=no
-AC_MSG_CHECKING([for $1])
-
-_PKG_CONFIG([$1][_CFLAGS], [cflags], [$2])
-_PKG_CONFIG([$1][_LIBS], [libs], [$2])
-
-m4_define([_PKG_TEXT], [Alternatively, you may set the environment variables $1[]_CFLAGS
-and $1[]_LIBS to avoid the need to call pkg-config.
-See the pkg-config man page for more details.])
-
-if test $pkg_failed = yes; then
- AC_MSG_RESULT([no])
- _PKG_SHORT_ERRORS_SUPPORTED
- if test $_pkg_short_errors_supported = yes; then
- $1[]_PKG_ERRORS=`$PKG_CONFIG --short-errors --print-errors --cflags --libs "$2" 2>&1`
- else
- $1[]_PKG_ERRORS=`$PKG_CONFIG --print-errors --cflags --libs "$2" 2>&1`
- fi
- # Put the nasty error message in config.log where it belongs
- echo "$$1[]_PKG_ERRORS" >&AS_MESSAGE_LOG_FD
-
- m4_default([$4], [AC_MSG_ERROR(
-[Package requirements ($2) were not met:
-
-$$1_PKG_ERRORS
-
-Consider adjusting the PKG_CONFIG_PATH environment variable if you
-installed software in a non-standard prefix.
-
-_PKG_TEXT])[]dnl
- ])
-elif test $pkg_failed = untried; then
- AC_MSG_RESULT([no])
- m4_default([$4], [AC_MSG_FAILURE(
-[The pkg-config script could not be found or is too old. Make sure it
-is in your PATH or set the PKG_CONFIG environment variable to the full
-path to pkg-config.
-
-_PKG_TEXT
-
-To get pkg-config, see .])[]dnl
- ])
-else
- $1[]_CFLAGS=$pkg_cv_[]$1[]_CFLAGS
- $1[]_LIBS=$pkg_cv_[]$1[]_LIBS
- AC_MSG_RESULT([yes])
- $3
-fi[]dnl
-])# PKG_CHECK_MODULES
-
-
-# PKG_INSTALLDIR(DIRECTORY)
-# -------------------------
-# Substitutes the variable pkgconfigdir as the location where a module
-# should install pkg-config .pc files. By default the directory is
-# $libdir/pkgconfig, but the default can be changed by passing
-# DIRECTORY. The user can override through the --with-pkgconfigdir
-# parameter.
-AC_DEFUN([PKG_INSTALLDIR],
-[m4_pushdef([pkg_default], [m4_default([$1], ['${libdir}/pkgconfig'])])
-m4_pushdef([pkg_description],
- [pkg-config installation directory @<:@]pkg_default[@:>@])
-AC_ARG_WITH([pkgconfigdir],
- [AS_HELP_STRING([--with-pkgconfigdir], pkg_description)],,
- [with_pkgconfigdir=]pkg_default)
-AC_SUBST([pkgconfigdir], [$with_pkgconfigdir])
-m4_popdef([pkg_default])
-m4_popdef([pkg_description])
-]) dnl PKG_INSTALLDIR
-
-
-# PKG_NOARCH_INSTALLDIR(DIRECTORY)
-# -------------------------
-# Substitutes the variable noarch_pkgconfigdir as the location where a
-# module should install arch-independent pkg-config .pc files. By
-# default the directory is $datadir/pkgconfig, but the default can be
-# changed by passing DIRECTORY. The user can override through the
-# --with-noarch-pkgconfigdir parameter.
-AC_DEFUN([PKG_NOARCH_INSTALLDIR],
-[m4_pushdef([pkg_default], [m4_default([$1], ['${datadir}/pkgconfig'])])
-m4_pushdef([pkg_description],
- [pkg-config arch-independent installation directory @<:@]pkg_default[@:>@])
-AC_ARG_WITH([noarch-pkgconfigdir],
- [AS_HELP_STRING([--with-noarch-pkgconfigdir], pkg_description)],,
- [with_noarch_pkgconfigdir=]pkg_default)
-AC_SUBST([noarch_pkgconfigdir], [$with_noarch_pkgconfigdir])
-m4_popdef([pkg_default])
-m4_popdef([pkg_description])
-]) dnl PKG_NOARCH_INSTALLDIR
-
-
-# PKG_CHECK_VAR(VARIABLE, MODULE, CONFIG-VARIABLE,
-# [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
-# -------------------------------------------
-# Retrieves the value of the pkg-config variable for the given module.
-AC_DEFUN([PKG_CHECK_VAR],
-[AC_REQUIRE([PKG_PROG_PKG_CONFIG])dnl
-AC_ARG_VAR([$1], [value of $3 for $2, overriding pkg-config])dnl
-
-_PKG_CONFIG([$1], [variable="][$3]["], [$2])
-AS_VAR_COPY([$1], [pkg_cv_][$1])
-
-AS_VAR_IF([$1], [""], [$5], [$4])dnl
-])# PKG_CHECK_VAR