Add Autotools-based build infrastructure

This makes it easier to package ddclient, especially as enhancements
are made such as unit tests or a man page.

I chose GNU Autoconf and Automake mostly because I'm familiar with
them, but also because I know they are well supported. Unfortunately
they can be difficult to understand/maintain (especially Autoconf), so
we may want to convert to something else later.

Addresses #146, #147

.gitignore

@@ -3,3 +3,15 @@ release
 .svn
 .cvsignore
 *~
+/Makefile
+/Makefile.in
+/aclocal.m4
+/autom4te.cache/
+/build-aux/install-sh
+/build-aux/missing
+/config.log
+/config.status
+/configure
+/ddclient
+/ddclient-*.tar.gz
+/ddclient.conf

ChangeLog.md

@@ -9,6 +9,10 @@ repository history](https://github.com/ddclient/ddclient/commits/master).
 
   * Added support for OVH DynHost.
   * Added support for ClouDNS.
+  * Added a build system to make it easier for distributions to package
+    ddclient:
+
+        ./autogen && ./configure && make && make install
 
 ### Bug fixes
 

Makefile.am

@@ -0,0 +1,58 @@
+ACLOCAL_AMFLAGS = -I m4
+EXTRA_DIST = \
+	CONTRIBUTING.md \
+	COPYING \
+	COPYRIGHT \
+	ChangeLog.md \
+	README.cisco \
+	README.md \
+	README.ssl \
+	TODO \
+	UPGRADE \
+	autogen \
+	sample-ddclient-wrapper.sh \
+	sample-etc_cron.d_ddclient \
+	sample-etc_dhclient-exit-hooks \
+	sample-etc_dhcpc_dhcpcd-eth0.exe \
+	sample-etc_ppp_ip-up.local \
+	sample-etc_rc.d_init.d_ddclient \
+	sample-etc_rc.d_init.d_ddclient.alpine \
+	sample-etc_rc.d_init.d_ddclient.lsb \
+	sample-etc_rc.d_init.d_ddclient.redhat \
+	sample-etc_rc.d_init.d_ddclient.ubuntu \
+	sample-etc_systemd.service \
+	sample-get-ip-from-fritzbox
+CLEANFILES =
+
+# Command that replaces substitution variables with their values.
+subst = sed \
+	-e 's|@PACKAGE_VERSION[@]|$(PACKAGE_VERSION)|g' \
+	-e 's|@PERL[@]|$(PERL)|g' \
+	-e 's|@localstatedir[@]|$(localstatedir)|g' \
+	-e 's|@runstatedir[@]|$(runstatedir)|g' \
+	-e 's|@sysconfdir[@]|$(sysconfdir)|g'
+
+# Files that will be generated by passing their *.template file
+# through $(subst).
+subst_files = ddclient ddclient.conf
+
+EXTRA_DIST += $(subst_files:=.template)
+CLEANFILES += $(subst_files)
+
+$(subst_files): Makefile
+	rm -f '$@' '$@'.tmp
+	in='$@'.template; \
+		test -f "$${in}" || in='$(srcdir)/'$${in}; \
+		$(subst) "$${in}" >'$@'.tmp && \
+		{ ! test -x "$${in}" || chmod +x '$@'.tmp; }
+	mv '$@'.tmp '$@'
+
+ddclient: $(srcdir)/ddclient.template
+ddclient.conf: $(srcdir)/ddclient.conf.template
+
+bin_SCRIPTS = ddclient
+
+sysconf_DATA = ddclient.conf
+
+install-data-local:
+	$(MKDIR_P) '$(DESTDIR)$(localstatedir)'/cache/ddclient

README.md

@@ -44,25 +44,47 @@ through github.com. Please check out http://ddclient.net
 
 ## REQUIREMENTS
 
-- one or more accounts from one of the dynamic DNS services
+  * An account from a supported dynamic DNS service provider
+  * Perl v5.10.1 or later
+      * `IO::Socket::SSL` perl library for ssl-support
+      * `JSON::PP` perl library for JSON support
+      * `IO::Socket:INET6` perl library for ipv6-support
+  * Linux, macOS, or any other Unix-ish system
+  * An implementation of `make` (such as [GNU
+    Make](https://www.gnu.org/software/make/))
+  * If you are installing from a clone of the Git repository, you will
+    also need [GNU Autoconf](https://www.gnu.org/software/autoconf/)
+    and [GNU Automake](https://www.gnu.org/software/automake/).
 
-- Perl v5.10.1 or later
+## DOWNLOAD
-  - `IO::Socket::SSL` perl library for ssl-support
-  - `JSON::PP` perl library for JSON support
-  - `IO::Socket:INET6` perl library for ipv6-support
 
-- Linux or probably any common Unix system
+See https://github.com/ddclient/ddclient/releases
-
--------------------------------------------------------------------------------
 
 ## INSTALLATION
 
-    cp ddclient /usr/sbin/
+  1. Extract the distribution tarball (`.tar.gz` file) and `cd` into
-    mkdir /etc/ddclient /var/cache/ddclient
+     the directory:
-    cp sample-etc_ddclient.conf /etc/ddclient/ddclient.conf
-    vi /etc/ddclient/ddclient.conf
 
-and change hostnames, logins, and passwords appropriately
+     ```shell
+     tar xvfa ddclient-3.9.1.tar.gz
+     cd ddclient-3.9.1
+     ```
+
+     (If you are installing from a clone of the Git repository, you
+     must run `./autogen` before continuing to the next step.)
+
+  2. Run the following commands to build and install:
+
+     ```shell
+     ./configure \
+         --prefix=/usr \
+         --sysconfdir=/etc/ddclient \
+         --localstatedir=/var
+     make
+     sudo make install
+     ```
+
+  3. Edit `/etc/ddclient/ddclient.conf`.
 
 ### systemd
 

autogen

@@ -0,0 +1,5 @@
+#!/bin/sh
+
+cd "${0%/*}" || exit 1
+mkdir -p m4 build-aux || exit 1
+exec autoreconf -fviW all

configure.ac

@@ -0,0 +1,23 @@
+AC_PREREQ([2.63])
+AC_INIT([ddclient], [3.9.1])
+AC_CONFIG_SRCDIR([ddclient.template])
+AC_CONFIG_AUX_DIR([build-aux])
+AC_CONFIG_MACRO_DIR([m4])
+AM_INIT_AUTOMAKE([1.11 -Wall -Werror foreign subdir-objects])
+AM_SILENT_RULES
+
+AC_PROG_MKDIR_P
+
+AX_WITH_PROG([PERL], perl)
+AX_PROG_PERL_VERSION([5.10.1], [],
+  [AC_MSG_ERROR([Perl 5.10.1 or newer not found])])
+AC_SUBST([PERL])
+
+m4_foreach_w([_m], [
+  ], [AX_PROG_PERL_MODULES([_m], [],
+         [AC_MSG_ERROR([missing required Perl module _m])])])
+
+AC_CONFIG_FILES([
+    Makefile
+  ])
+AC_OUTPUT

ddclient.conf.template

@@ -20,7 +20,7 @@ daemon=300				# check every 300 seconds
 syslog=yes				# log update msgs to syslog
 mail=root				# mail all msgs to root
 mail-failure=root			# mail failed update msgs to root
-pid=/var/run/ddclient.pid		# record PID in file.
+pid=@runstatedir@/ddclient.pid		# record PID in file.
 ssl=yes					# use ssl-support.  Works with
 					# ssl-library
 # postscript=script			# run script after updating.  The

ddclient.template

@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!@PERL@
 ######################################################################
 #
 # DDCLIENT - a Perl client for updating DynDNS information
@@ -32,9 +32,25 @@ my $program = $programd;
 $program =~ s/d$//;
 my $now = time;
 my $hostname = hostname();
-my $etc       = ($program =~ /test/i) ? './'   : '/etc/ddclient/';
+
-my $cachedir  = ($program =~ /test/i) ? './'   : '/var/cache/ddclient/';
+# subst_var(subst, default) returns subst unless it looks like @foo@ in which case it returns
-my $savedir   = ($program =~ /test/i) ? 'URL/' : '/tmp/';
+# default. The @foo@ strings are expected to be replaced by make; this function makes it possible
+# to run this file as a Perl script before those substitutions are made.
+sub subst_var {
+    my ($subst, $default) = @_;
+    return $default if $subst =~ /^@\w+@$/a;
+    return $subst;
+}
+
+my $etc = subst_var('@sysconfdir@', '/etc/ddclient');
+my $cachedir = subst_var('@localstatedir@', '/var') . '/cache/ddclient';
+my $savedir = '/tmp';
+if ($program =~ /test/i) {
+    $etc = '.';
+    $cachedir = '.';
+    $savedir = 'URL';
+}
+
 my $msgs      = '';
 my $last_msgs = '';
 
@@ -321,8 +337,8 @@ my %variables = (
     'global-defaults' => {
         'daemon'              => setv(T_DELAY, 0, 0, $daemon_default,      interval('60s')),
         'foreground'          => setv(T_BOOL,  0, 0, 0,                    undef),
-        'file'                => setv(T_FILE,  0, 0, "$etc$program.conf",  undef),
+        'file'                => setv(T_FILE,  0, 0, "$etc/$program.conf", undef),
-        'cache'               => setv(T_FILE,  0, 0, "$cachedir$program.cache", undef),
+        'cache'               => setv(T_FILE,  0, 0, "$cachedir/$program.cache", undef),
         'pid'                 => setv(T_FILE,  0, 0, "",                   undef),
         'proxy'               => setv(T_FQDNP, 0, 0, '',                   undef),
         'protocol'            => setv(T_PROTO, 0, 0, 'dyndns2',            undef),
@@ -2157,9 +2173,9 @@ sub geturl {
         my $filename = "$server/$url";
         $filename =~ s|/|%2F|g;
         if (opt('exec')) {
-            $reply = save_file("${savedir}$filename", $reply, 'unique');
+            $reply = save_file("$savedir/$filename", $reply, 'unique');
         } else {
-            $reply = load_file("${savedir}$filename");
+            $reply = load_file("$savedir/$filename");
         }
     }
 

m4/ax_compare_version.m4

@@ -0,0 +1,177 @@
+# ===========================================================================
+#    https://www.gnu.org/software/autoconf-archive/ax_compare_version.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_COMPARE_VERSION(VERSION_A, OP, VERSION_B, [ACTION-IF-TRUE], [ACTION-IF-FALSE])
+#
+# DESCRIPTION
+#
+#   This macro compares two version strings. Due to the various number of
+#   minor-version numbers that can exist, and the fact that string
+#   comparisons are not compatible with numeric comparisons, this is not
+#   necessarily trivial to do in a autoconf script. This macro makes doing
+#   these comparisons easy.
+#
+#   The six basic comparisons are available, as well as checking equality
+#   limited to a certain number of minor-version levels.
+#
+#   The operator OP determines what type of comparison to do, and can be one
+#   of:
+#
+#    eq  - equal (test A == B)
+#    ne  - not equal (test A != B)
+#    le  - less than or equal (test A <= B)
+#    ge  - greater than or equal (test A >= B)
+#    lt  - less than (test A < B)
+#    gt  - greater than (test A > B)
+#
+#   Additionally, the eq and ne operator can have a number after it to limit
+#   the test to that number of minor versions.
+#
+#    eq0 - equal up to the length of the shorter version
+#    ne0 - not equal up to the length of the shorter version
+#    eqN - equal up to N sub-version levels
+#    neN - not equal up to N sub-version levels
+#
+#   When the condition is true, shell commands ACTION-IF-TRUE are run,
+#   otherwise shell commands ACTION-IF-FALSE are run. The environment
+#   variable 'ax_compare_version' is always set to either 'true' or 'false'
+#   as well.
+#
+#   Examples:
+#
+#     AX_COMPARE_VERSION([3.15.7],[lt],[3.15.8])
+#     AX_COMPARE_VERSION([3.15],[lt],[3.15.8])
+#
+#   would both be true.
+#
+#     AX_COMPARE_VERSION([3.15.7],[eq],[3.15.8])
+#     AX_COMPARE_VERSION([3.15],[gt],[3.15.8])
+#
+#   would both be false.
+#
+#     AX_COMPARE_VERSION([3.15.7],[eq2],[3.15.8])
+#
+#   would be true because it is only comparing two minor versions.
+#
+#     AX_COMPARE_VERSION([3.15.7],[eq0],[3.15])
+#
+#   would be true because it is only comparing the lesser number of minor
+#   versions of the two values.
+#
+#   Note: The characters that separate the version numbers do not matter. An
+#   empty string is the same as version 0. OP is evaluated by autoconf, not
+#   configure, so must be a string, not a variable.
+#
+#   The author would like to acknowledge Guido Draheim whose advice about
+#   the m4_case and m4_ifvaln functions make this macro only include the
+#   portions necessary to perform the specific comparison specified by the
+#   OP argument in the final configure script.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Tim Toolan <toolan@ele.uri.edu>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 13
+
+dnl #########################################################################
+AC_DEFUN([AX_COMPARE_VERSION], [
+  AC_REQUIRE([AC_PROG_AWK])
+
+  # Used to indicate true or false condition
+  ax_compare_version=false
+
+  # Convert the two version strings to be compared into a format that
+  # allows a simple string comparison.  The end result is that a version
+  # string of the form 1.12.5-r617 will be converted to the form
+  # 0001001200050617.  In other words, each number is zero padded to four
+  # digits, and non digits are removed.
+  AS_VAR_PUSHDEF([A],[ax_compare_version_A])
+  A=`echo "$1" | sed -e 's/\([[0-9]]*\)/Z\1Z/g' \
+                     -e 's/Z\([[0-9]]\)Z/Z0\1Z/g' \
+                     -e 's/Z\([[0-9]][[0-9]]\)Z/Z0\1Z/g' \
+                     -e 's/Z\([[0-9]][[0-9]][[0-9]]\)Z/Z0\1Z/g' \
+                     -e 's/[[^0-9]]//g'`
+
+  AS_VAR_PUSHDEF([B],[ax_compare_version_B])
+  B=`echo "$3" | sed -e 's/\([[0-9]]*\)/Z\1Z/g' \
+                     -e 's/Z\([[0-9]]\)Z/Z0\1Z/g' \
+                     -e 's/Z\([[0-9]][[0-9]]\)Z/Z0\1Z/g' \
+                     -e 's/Z\([[0-9]][[0-9]][[0-9]]\)Z/Z0\1Z/g' \
+                     -e 's/[[^0-9]]//g'`
+
+  dnl # In the case of le, ge, lt, and gt, the strings are sorted as necessary
+  dnl # then the first line is used to determine if the condition is true.
+  dnl # The sed right after the echo is to remove any indented white space.
+  m4_case(m4_tolower($2),
+  [lt],[
+    ax_compare_version=`echo "x$A
+x$B" | sed 's/^ *//' | sort -r | sed "s/x${A}/false/;s/x${B}/true/;1q"`
+  ],
+  [gt],[
+    ax_compare_version=`echo "x$A
+x$B" | sed 's/^ *//' | sort | sed "s/x${A}/false/;s/x${B}/true/;1q"`
+  ],
+  [le],[
+    ax_compare_version=`echo "x$A
+x$B" | sed 's/^ *//' | sort | sed "s/x${A}/true/;s/x${B}/false/;1q"`
+  ],
+  [ge],[
+    ax_compare_version=`echo "x$A
+x$B" | sed 's/^ *//' | sort -r | sed "s/x${A}/true/;s/x${B}/false/;1q"`
+  ],[
+    dnl Split the operator from the subversion count if present.
+    m4_bmatch(m4_substr($2,2),
+    [0],[
+      # A count of zero means use the length of the shorter version.
+      # Determine the number of characters in A and B.
+      ax_compare_version_len_A=`echo "$A" | $AWK '{print(length)}'`
+      ax_compare_version_len_B=`echo "$B" | $AWK '{print(length)}'`
+
+      # Set A to no more than B's length and B to no more than A's length.
+      A=`echo "$A" | sed "s/\(.\{$ax_compare_version_len_B\}\).*/\1/"`
+      B=`echo "$B" | sed "s/\(.\{$ax_compare_version_len_A\}\).*/\1/"`
+    ],
+    [[0-9]+],[
+      # A count greater than zero means use only that many subversions
+      A=`echo "$A" | sed "s/\(\([[0-9]]\{4\}\)\{m4_substr($2,2)\}\).*/\1/"`
+      B=`echo "$B" | sed "s/\(\([[0-9]]\{4\}\)\{m4_substr($2,2)\}\).*/\1/"`
+    ],
+    [.+],[
+      AC_WARNING(
+        [invalid OP numeric parameter: $2])
+    ],[])
+
+    # Pad zeros at end of numbers to make same length.
+    ax_compare_version_tmp_A="$A`echo $B | sed 's/./0/g'`"
+    B="$B`echo $A | sed 's/./0/g'`"
+    A="$ax_compare_version_tmp_A"
+
+    # Check for equality or inequality as necessary.
+    m4_case(m4_tolower(m4_substr($2,0,2)),
+    [eq],[
+      test "x$A" = "x$B" && ax_compare_version=true
+    ],
+    [ne],[
+      test "x$A" != "x$B" && ax_compare_version=true
+    ],[
+      AC_WARNING([invalid OP parameter: $2])
+    ])
+  ])
+
+  AS_VAR_POPDEF([A])dnl
+  AS_VAR_POPDEF([B])dnl
+
+  dnl # Execute ACTION-IF-TRUE / ACTION-IF-FALSE.
+  if test "$ax_compare_version" = "true" ; then
+    m4_ifvaln([$4],[$4],[:])dnl
+    m4_ifvaln([$5],[else $5])dnl
+  fi
+]) dnl AX_COMPARE_VERSION

m4/ax_prog_perl_modules.m4

@@ -0,0 +1,77 @@
+# ===========================================================================
+#   https://www.gnu.org/software/autoconf-archive/ax_prog_perl_modules.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_PROG_PERL_MODULES([MODULES], [ACTION-IF-TRUE], [ACTION-IF-FALSE])
+#
+# DESCRIPTION
+#
+#   Checks to see if the given perl modules are available. If true the shell
+#   commands in ACTION-IF-TRUE are executed. If not the shell commands in
+#   ACTION-IF-FALSE are run. Note if $PERL is not set (for example by
+#   calling AC_CHECK_PROG, or AC_PATH_PROG), AC_CHECK_PROG(PERL, perl, perl)
+#   will be run.
+#
+#   MODULES is a space separated list of module names. To check for a
+#   minimum version of a module, append the version number to the module
+#   name, separated by an equals sign.
+#
+#   Example:
+#
+#     AX_PROG_PERL_MODULES( Text::Wrap Net::LDAP=1.0.3, ,
+#                           AC_MSG_WARN(Need some Perl modules)
+#
+# LICENSE
+#
+#   Copyright (c) 2009 Dean Povey <povey@wedgetail.com>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 8
+
+AU_ALIAS([AC_PROG_PERL_MODULES], [AX_PROG_PERL_MODULES])
+AC_DEFUN([AX_PROG_PERL_MODULES],[dnl
+
+m4_define([ax_perl_modules])
+m4_foreach([ax_perl_module], m4_split(m4_normalize([$1])),
+	  [
+	   m4_append([ax_perl_modules],
+		     [']m4_bpatsubst(ax_perl_module,=,[ ])[' ])
+          ])
+
+# Make sure we have perl
+if test -z "$PERL"; then
+AC_CHECK_PROG(PERL,perl,perl)
+fi
+
+if test "x$PERL" != x; then
+  ax_perl_modules_failed=0
+  for ax_perl_module in ax_perl_modules; do
+    AC_MSG_CHECKING(for perl module $ax_perl_module)
+
+    # Would be nice to log result here, but can't rely on autoconf internals
+    $PERL -e "use $ax_perl_module; exit" > /dev/null 2>&1
+    if test $? -ne 0; then
+      AC_MSG_RESULT(no);
+      ax_perl_modules_failed=1
+   else
+      AC_MSG_RESULT(ok);
+    fi
+  done
+
+  # Run optional shell commands
+  if test "$ax_perl_modules_failed" = 0; then
+    :
+    $2
+  else
+    :
+    $3
+  fi
+else
+  AC_MSG_WARN(could not find perl)
+fi])dnl

m4/ax_prog_perl_version.m4

@@ -0,0 +1,70 @@
+# ===========================================================================
+#   https://www.gnu.org/software/autoconf-archive/ax_prog_perl_version.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_PROG_PERL_VERSION([VERSION],[ACTION-IF-TRUE],[ACTION-IF-FALSE])
+#
+# DESCRIPTION
+#
+#   Makes sure that perl supports the version indicated. If true the shell
+#   commands in ACTION-IF-TRUE are executed. If not the shell commands in
+#   ACTION-IF-FALSE are run. Note if $PERL is not set (for example by
+#   running AC_CHECK_PROG or AC_PATH_PROG) the macro will fail.
+#
+#   Example:
+#
+#     AC_PATH_PROG([PERL],[perl])
+#     AX_PROG_PERL_VERSION([5.8.0],[ ... ],[ ... ])
+#
+#   This will check to make sure that the perl you have supports at least
+#   version 5.8.0.
+#
+#   NOTE: This macro uses the $PERL variable to perform the check.
+#   AX_WITH_PERL can be used to set that variable prior to running this
+#   macro. The $PERL_VERSION variable will be valorized with the detected
+#   version.
+#
+# LICENSE
+#
+#   Copyright (c) 2009 Francesco Salvestrini <salvestrini@users.sourceforge.net>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 13
+
+AC_DEFUN([AX_PROG_PERL_VERSION],[
+    AC_REQUIRE([AC_PROG_SED])
+    AC_REQUIRE([AC_PROG_GREP])
+
+    AS_IF([test -n "$PERL"],[
+        ax_perl_version="$1"
+
+        AC_MSG_CHECKING([for perl version])
+        changequote(<<,>>)
+        perl_version=`$PERL --version 2>&1 \
+          | $SED -n -e '/This is perl/b inspect
+b
+: inspect
+s/.* (\{0,1\}v\([0-9]*\.[0-9]*\.[0-9]*\))\{0,1\} .*/\1/;p'`
+        changequote([,])
+        AC_MSG_RESULT($perl_version)
+
+	AC_SUBST([PERL_VERSION],[$perl_version])
+
+        AX_COMPARE_VERSION([$ax_perl_version],[le],[$perl_version],[
+	    :
+            $2
+        ],[
+	    :
+            $3
+        ])
+    ],[
+        AC_MSG_WARN([could not find the perl interpreter])
+        $3
+    ])
+])

m4/ax_with_prog.m4

@@ -0,0 +1,70 @@
+# ===========================================================================
+#       https://www.gnu.org/software/autoconf-archive/ax_with_prog.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_WITH_PROG([VARIABLE],[program],[VALUE-IF-NOT-FOUND],[PATH])
+#
+# DESCRIPTION
+#
+#   Locates an installed program binary, placing the result in the precious
+#   variable VARIABLE. Accepts a present VARIABLE, then --with-program, and
+#   failing that searches for program in the given path (which defaults to
+#   the system path). If program is found, VARIABLE is set to the full path
+#   of the binary; if it is not found VARIABLE is set to VALUE-IF-NOT-FOUND
+#   if provided, unchanged otherwise.
+#
+#   A typical example could be the following one:
+#
+#     AX_WITH_PROG(PERL,perl)
+#
+#   NOTE: This macro is based upon the original AX_WITH_PYTHON macro from
+#   Dustin J. Mitchell <dustin@cs.uchicago.edu>.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Francesco Salvestrini <salvestrini@users.sourceforge.net>
+#   Copyright (c) 2008 Dustin J. Mitchell <dustin@cs.uchicago.edu>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 17
+
+AC_DEFUN([AX_WITH_PROG],[
+    AC_PREREQ([2.61])
+
+    pushdef([VARIABLE],$1)
+    pushdef([EXECUTABLE],$2)
+    pushdef([VALUE_IF_NOT_FOUND],$3)
+    pushdef([PATH_PROG],$4)
+
+    AC_ARG_VAR(VARIABLE,Absolute path to EXECUTABLE executable)
+
+    AS_IF(test -z "$VARIABLE",[
+        AC_MSG_CHECKING(whether EXECUTABLE executable path has been provided)
+        AC_ARG_WITH(EXECUTABLE,AS_HELP_STRING([--with-EXECUTABLE=[[[PATH]]]],absolute path to EXECUTABLE executable), [
+            AS_IF([test "$withval" != yes && test "$withval" != no],[
+                VARIABLE="$withval"
+                AC_MSG_RESULT($VARIABLE)
+            ],[
+                VARIABLE=""
+                AC_MSG_RESULT([no])
+                AS_IF([test "$withval" != no], [
+                  AC_PATH_PROG([]VARIABLE[],[]EXECUTABLE[],[]VALUE_IF_NOT_FOUND[],[]PATH_PROG[])
+                ])
+            ])
+        ],[
+            AC_MSG_RESULT([no])
+            AC_PATH_PROG([]VARIABLE[],[]EXECUTABLE[],[]VALUE_IF_NOT_FOUND[],[]PATH_PROG[])
+        ])
+    ])
+
+    popdef([PATH_PROG])
+    popdef([VALUE_IF_NOT_FOUND])
+    popdef([EXECUTABLE])
+    popdef([VARIABLE])
+])