--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/curl/m4/curl-confopts.m4	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,650 @@
+#***************************************************************************
+#                                  _   _ ____  _
+#  Project                     ___| | | |  _ \| |
+#                             / __| | | | |_) | |
+#                            | (__| |_| |  _ <| |___
+#                             \___|\___/|_| \_\_____|
+#
+# Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@haxx.se>, et al.
+#
+# This software is licensed as described in the file COPYING, which
+# you should have received as part of this distribution. The terms
+# are also available at https://curl.haxx.se/docs/copyright.html.
+#
+# You may opt to use, copy, modify, merge, publish, distribute and/or sell
+# copies of the Software, and permit persons to whom the Software is
+# furnished to do so, under the terms of the COPYING file.
+#
+# This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+# KIND, either express or implied.
+#
+#***************************************************************************
+
+# File version for 'aclocal' use. Keep it a single number.
+# serial 19
+
+dnl CURL_CHECK_OPTION_THREADED_RESOLVER
+dnl -------------------------------------------------
+dnl Verify if configure has been invoked with option
+dnl --enable-threaded-resolver or --disable-threaded-resolver, and
+dnl set shell variable want_thres as appropriate.
+
+AC_DEFUN([CURL_CHECK_OPTION_THREADED_RESOLVER], [
+  AC_MSG_CHECKING([whether to enable the threaded resolver])
+  OPT_THRES="default"
+  AC_ARG_ENABLE(threaded_resolver,
+AC_HELP_STRING([--enable-threaded-resolver],[Enable threaded resolver])
+AC_HELP_STRING([--disable-threaded-resolver],[Disable threaded resolver]),
+  OPT_THRES=$enableval)
+  case "$OPT_THRES" in
+    no)
+      dnl --disable-threaded-resolver option used
+      want_thres="no"
+      ;;
+    *)
+      dnl configure option not specified
+      want_thres="yes"
+      ;;
+  esac
+  AC_MSG_RESULT([$want_thres])
+])
+
+dnl CURL_CHECK_OPTION_ARES
+dnl -------------------------------------------------
+dnl Verify if configure has been invoked with option
+dnl --enable-ares or --disable-ares, and
+dnl set shell variable want_ares as appropriate.
+
+AC_DEFUN([CURL_CHECK_OPTION_ARES], [
+dnl   AC_BEFORE([$0],[CURL_CHECK_OPTION_THREADS])dnl
+  AC_BEFORE([$0],[CURL_CHECK_LIB_ARES])dnl
+  AC_MSG_CHECKING([whether to enable c-ares for DNS lookups])
+  OPT_ARES="default"
+  AC_ARG_ENABLE(ares,
+AC_HELP_STRING([--enable-ares@<:@=PATH@:>@],[Enable c-ares for DNS lookups])
+AC_HELP_STRING([--disable-ares],[Disable c-ares for DNS lookups]),
+  OPT_ARES=$enableval)
+  case "$OPT_ARES" in
+    no)
+      dnl --disable-ares option used
+      want_ares="no"
+      ;;
+    default)
+      dnl configure option not specified
+      want_ares="no"
+      ;;
+    *)
+      dnl --enable-ares option used
+      want_ares="yes"
+      if test -n "$enableval" && test "$enableval" != "yes"; then
+        want_ares_path="$enableval"
+      fi
+      ;;
+  esac
+  AC_MSG_RESULT([$want_ares])
+])
+
+
+dnl CURL_CHECK_OPTION_CURLDEBUG
+dnl -------------------------------------------------
+dnl Verify if configure has been invoked with option
+dnl --enable-curldebug or --disable-curldebug, and set
+dnl shell variable want_curldebug value as appropriate.
+
+AC_DEFUN([CURL_CHECK_OPTION_CURLDEBUG], [
+  AC_BEFORE([$0],[CURL_CHECK_CURLDEBUG])dnl
+  AC_MSG_CHECKING([whether to enable curl debug memory tracking])
+  OPT_CURLDEBUG_BUILD="default"
+  AC_ARG_ENABLE(curldebug,
+AC_HELP_STRING([--enable-curldebug],[Enable curl debug memory tracking])
+AC_HELP_STRING([--disable-curldebug],[Disable curl debug memory tracking]),
+  OPT_CURLDEBUG_BUILD=$enableval)
+  case "$OPT_CURLDEBUG_BUILD" in
+    no)
+      dnl --disable-curldebug option used
+      want_curldebug="no"
+      AC_MSG_RESULT([no])
+      ;;
+    default)
+      dnl configure's curldebug option not specified. Initially we will
+      dnl handle this as a a request to use the same setting as option
+      dnl --enable-debug. IOW, initially, for debug-enabled builds
+      dnl this will be handled as a request to enable curldebug if
+      dnl possible, and for debug-disabled builds this will be handled
+      dnl as a request to disable curldebug.
+      if test "$want_debug" = "yes"; then
+        AC_MSG_RESULT([(assumed) yes])
+        AC_DEFINE(CURLDEBUG, 1, [to enable curl debug memory tracking])
+      else
+        AC_MSG_RESULT([no])
+      fi
+      want_curldebug_assumed="yes"
+      want_curldebug="$want_debug"
+      ;;
+    *)
+      dnl --enable-curldebug option used.
+      dnl The use of this option value is a request to enable curl's
+      dnl debug memory tracking for the libcurl library. This can only
+      dnl be done when some requisites are simultaneously satisfied.
+      dnl Later on, these requisites are verified and if they are not
+      dnl fully satisfied the option will be ignored and act as if
+      dnl --disable-curldebug had been given setting shell variable
+      dnl want_curldebug to 'no'.
+      want_curldebug="yes"
+      AC_DEFINE(CURLDEBUG, 1, [to enable curl debug memory tracking])
+      AC_MSG_RESULT([yes])
+      ;;
+  esac
+])
+
+
+dnl CURL_CHECK_OPTION_DEBUG
+dnl -------------------------------------------------
+dnl Verify if configure has been invoked with option
+dnl --enable-debug or --disable-debug, and set shell
+dnl variable want_debug value as appropriate.
+
+AC_DEFUN([CURL_CHECK_OPTION_DEBUG], [
+  AC_BEFORE([$0],[CURL_CHECK_OPTION_WARNINGS])dnl
+  AC_BEFORE([$0],[CURL_CHECK_OPTION_CURLDEBUG])dnl
+  AC_BEFORE([$0],[XC_CHECK_PROG_CC])dnl
+  AC_MSG_CHECKING([whether to enable debug build options])
+  OPT_DEBUG_BUILD="default"
+  AC_ARG_ENABLE(debug,
+AC_HELP_STRING([--enable-debug],[Enable debug build options])
+AC_HELP_STRING([--disable-debug],[Disable debug build options]),
+  OPT_DEBUG_BUILD=$enableval)
+  case "$OPT_DEBUG_BUILD" in
+    no)
+      dnl --disable-debug option used
+      want_debug="no"
+      ;;
+    default)
+      dnl configure option not specified
+      want_debug="no"
+      ;;
+    *)
+      dnl --enable-debug option used
+      want_debug="yes"
+      AC_DEFINE(DEBUGBUILD, 1, [enable debug build options])
+      ;;
+  esac
+  AC_MSG_RESULT([$want_debug])
+])
+
+dnl CURL_CHECK_OPTION_OPTIMIZE
+dnl -------------------------------------------------
+dnl Verify if configure has been invoked with option
+dnl --enable-optimize or --disable-optimize, and set
+dnl shell variable want_optimize value as appropriate.
+
+AC_DEFUN([CURL_CHECK_OPTION_OPTIMIZE], [
+  AC_REQUIRE([CURL_CHECK_OPTION_DEBUG])dnl
+  AC_BEFORE([$0],[XC_CHECK_PROG_CC])dnl
+  AC_MSG_CHECKING([whether to enable compiler optimizer])
+  OPT_COMPILER_OPTIMIZE="default"
+  AC_ARG_ENABLE(optimize,
+AC_HELP_STRING([--enable-optimize],[Enable compiler optimizations])
+AC_HELP_STRING([--disable-optimize],[Disable compiler optimizations]),
+  OPT_COMPILER_OPTIMIZE=$enableval)
+  case "$OPT_COMPILER_OPTIMIZE" in
+    no)
+      dnl --disable-optimize option used. We will handle this as
+      dnl a request to disable compiler optimizations if possible.
+      dnl If the compiler is known CFLAGS and CPPFLAGS will be
+      dnl overridden, otherwise this can not be honored.
+      want_optimize="no"
+      AC_MSG_RESULT([no])
+      ;;
+    default)
+      dnl configure's optimize option not specified. Initially we will
+      dnl handle this as a a request contrary to configure's setting
+      dnl for --enable-debug. IOW, initially, for debug-enabled builds
+      dnl this will be handled as a request to disable optimizations if
+      dnl possible, and for debug-disabled builds this will be handled
+      dnl initially as a request to enable optimizations if possible.
+      dnl Finally, if the compiler is known and CFLAGS and CPPFLAGS do
+      dnl not have any optimizer flag the request will be honored, in
+      dnl any other case the request can not be honored.
+      dnl IOW, existing optimizer flags defined in CFLAGS or CPPFLAGS
+      dnl will always take precedence over any initial assumption.
+      if test "$want_debug" = "yes"; then
+        want_optimize="assume_no"
+        AC_MSG_RESULT([(assumed) no])
+      else
+        want_optimize="assume_yes"
+        AC_MSG_RESULT([(assumed) yes])
+      fi
+      ;;
+    *)
+      dnl --enable-optimize option used. We will handle this as
+      dnl a request to enable compiler optimizations if possible.
+      dnl If the compiler is known CFLAGS and CPPFLAGS will be
+      dnl overridden, otherwise this can not be honored.
+      want_optimize="yes"
+      AC_MSG_RESULT([yes])
+      ;;
+  esac
+])
+
+
+dnl CURL_CHECK_OPTION_SYMBOL_HIDING
+dnl -------------------------------------------------
+dnl Verify if configure has been invoked with option
+dnl --enable-symbol-hiding or --disable-symbol-hiding,
+dnl setting shell variable want_symbol_hiding value.
+
+AC_DEFUN([CURL_CHECK_OPTION_SYMBOL_HIDING], [
+  AC_BEFORE([$0],[CURL_CHECK_COMPILER_SYMBOL_HIDING])dnl
+  AC_MSG_CHECKING([whether to enable hiding of library internal symbols])
+  OPT_SYMBOL_HIDING="default"
+  AC_ARG_ENABLE(symbol-hiding,
+AC_HELP_STRING([--enable-symbol-hiding],[Enable hiding of library internal symbols])
+AC_HELP_STRING([--disable-symbol-hiding],[Disable hiding of library internal symbols]),
+  OPT_SYMBOL_HIDING=$enableval)
+  AC_ARG_ENABLE(hidden-symbols,
+AC_HELP_STRING([--enable-hidden-symbols],[To be deprecated, use --enable-symbol-hiding])
+AC_HELP_STRING([--disable-hidden-symbols],[To be deprecated, use --disable-symbol-hiding]),
+  OPT_SYMBOL_HIDING=$enableval)
+  case "$OPT_SYMBOL_HIDING" in
+    no)
+      dnl --disable-symbol-hiding option used.
+      dnl This is an indication to not attempt hiding of library internal
+      dnl symbols. Default symbol visibility will be used, which normally
+      dnl exposes all library internal symbols.
+      want_symbol_hiding="no"
+      AC_MSG_RESULT([no])
+      ;;
+    default)
+      dnl configure's symbol-hiding option not specified.
+      dnl Handle this as if --enable-symbol-hiding option was given.
+      want_symbol_hiding="yes"
+      AC_MSG_RESULT([yes])
+      ;;
+    *)
+      dnl --enable-symbol-hiding option used.
+      dnl This is an indication to attempt hiding of library internal
+      dnl symbols. This is only supported on some compilers/linkers.
+      want_symbol_hiding="yes"
+      AC_MSG_RESULT([yes])
+      ;;
+  esac
+])
+
+
+dnl CURL_CHECK_OPTION_THREADS
+dnl -------------------------------------------------
+dnl Verify if configure has been invoked with option
+dnl --enable-threads or --disable-threads, and
+dnl set shell variable want_threads as appropriate.
+
+dnl AC_DEFUN([CURL_CHECK_OPTION_THREADS], [
+dnl   AC_BEFORE([$0],[CURL_CHECK_LIB_THREADS])dnl
+dnl   AC_MSG_CHECKING([whether to enable threads for DNS lookups])
+dnl   OPT_THREADS="default"
+dnl   AC_ARG_ENABLE(threads,
+dnl AC_HELP_STRING([--enable-threads@<:@=PATH@:>@],[Enable threads for DNS lookups])
+dnl AC_HELP_STRING([--disable-threads],[Disable threads for DNS lookups]),
+dnl   OPT_THREADS=$enableval)
+dnl   case "$OPT_THREADS" in
+dnl     no)
+dnl       dnl --disable-threads option used
+dnl       want_threads="no"
+dnl       AC_MSG_RESULT([no])
+dnl       ;;
+dnl     default)
+dnl       dnl configure option not specified
+dnl       want_threads="no"
+dnl       AC_MSG_RESULT([(assumed) no])
+dnl       ;;
+dnl     *)
+dnl       dnl --enable-threads option used
+dnl       want_threads="yes"
+dnl       want_threads_path="$enableval"
+dnl       AC_MSG_RESULT([yes])
+dnl       ;;
+dnl   esac
+dnl   #
+dnl   if test "$want_ares" = "assume_yes"; then
+dnl     if test "$want_threads" = "yes"; then
+dnl       AC_MSG_CHECKING([whether to ignore c-ares enabling assumed setting])
+dnl       AC_MSG_RESULT([yes])
+dnl       want_ares="no"
+dnl     else
+dnl       want_ares="yes"
+dnl     fi
+dnl   fi
+dnl   if test "$want_threads" = "yes" && test "$want_ares" = "yes"; then
+dnl     AC_MSG_ERROR([options --enable-ares and --enable-threads are mutually exclusive, at most one may be enabled.])
+dnl   fi
+dnl ])
+
+dnl CURL_CHECK_OPTION_RT
+dnl -------------------------------------------------
+dnl Verify if configure has been invoked with option
+dnl --disable-rt and set shell variable dontwant_rt
+dnl as appropriate.
+
+AC_DEFUN([CURL_CHECK_OPTION_RT], [
+  AC_BEFORE([$0], [CURL_CHECK_LIB_THREADS])dnl
+  AC_MSG_CHECKING([whether to disable dependency on -lrt])
+  OPT_RT="default"
+  AC_ARG_ENABLE(rt,
+ AC_HELP_STRING([--disable-rt],[disable dependency on -lrt]),
+  OPT_RT=$enableval)
+  case "$OPT_RT" in
+    no)
+      dnl --disable-rt used (reverse logic)
+      dontwant_rt="yes"
+      AC_MSG_RESULT([yes])
+      ;;
+    default)
+      dnl configure option not specified (so not disabled)
+      dontwant_rt="no"
+      AC_MSG_RESULT([(assumed no)])
+      ;;
+    *)
+      dnl --enable-rt option used (reverse logic)
+      dontwant_rt="no"
+      AC_MSG_RESULT([no])
+      ;;
+  esac
+])
+
+dnl CURL_CHECK_OPTION_WARNINGS
+dnl -------------------------------------------------
+dnl Verify if configure has been invoked with option
+dnl --enable-warnings or --disable-warnings, and set
+dnl shell variable want_warnings as appropriate.
+
+AC_DEFUN([CURL_CHECK_OPTION_WARNINGS], [
+  AC_REQUIRE([CURL_CHECK_OPTION_DEBUG])dnl
+  AC_BEFORE([$0],[CURL_CHECK_OPTION_WERROR])dnl
+  AC_BEFORE([$0],[XC_CHECK_PROG_CC])dnl
+  AC_MSG_CHECKING([whether to enable strict compiler warnings])
+  OPT_COMPILER_WARNINGS="default"
+  AC_ARG_ENABLE(warnings,
+AC_HELP_STRING([--enable-warnings],[Enable strict compiler warnings])
+AC_HELP_STRING([--disable-warnings],[Disable strict compiler warnings]),
+  OPT_COMPILER_WARNINGS=$enableval)
+  case "$OPT_COMPILER_WARNINGS" in
+    no)
+      dnl --disable-warnings option used
+      want_warnings="no"
+      ;;
+    default)
+      dnl configure option not specified, so
+      dnl use same setting as --enable-debug
+      want_warnings="$want_debug"
+      ;;
+    *)
+      dnl --enable-warnings option used
+      want_warnings="yes"
+      ;;
+  esac
+  AC_MSG_RESULT([$want_warnings])
+])
+
+dnl CURL_CHECK_OPTION_WERROR
+dnl -------------------------------------------------
+dnl Verify if configure has been invoked with option
+dnl --enable-werror or --disable-werror, and set
+dnl shell variable want_werror as appropriate.
+
+AC_DEFUN([CURL_CHECK_OPTION_WERROR], [
+  AC_BEFORE([$0],[CURL_CHECK_COMPILER])dnl
+  AC_MSG_CHECKING([whether to enable compiler warnings as errors])
+  OPT_COMPILER_WERROR="default"
+  AC_ARG_ENABLE(werror,
+AC_HELP_STRING([--enable-werror],[Enable compiler warnings as errors])
+AC_HELP_STRING([--disable-werror],[Disable compiler warnings as errors]),
+  OPT_COMPILER_WERROR=$enableval)
+  case "$OPT_COMPILER_WERROR" in
+    no)
+      dnl --disable-werror option used
+      want_werror="no"
+      ;;
+    default)
+      dnl configure option not specified
+      want_werror="no"
+      ;;
+    *)
+      dnl --enable-werror option used
+      want_werror="yes"
+      ;;
+  esac
+  AC_MSG_RESULT([$want_werror])
+])
+
+
+dnl CURL_CHECK_NONBLOCKING_SOCKET
+dnl -------------------------------------------------
+dnl Check for how to set a socket into non-blocking state.
+
+AC_DEFUN([CURL_CHECK_NONBLOCKING_SOCKET], [
+  AC_REQUIRE([CURL_CHECK_FUNC_FCNTL])dnl
+  AC_REQUIRE([CURL_CHECK_FUNC_IOCTL])dnl
+  AC_REQUIRE([CURL_CHECK_FUNC_IOCTLSOCKET])dnl
+  AC_REQUIRE([CURL_CHECK_FUNC_IOCTLSOCKET_CAMEL])dnl
+  AC_REQUIRE([CURL_CHECK_FUNC_SETSOCKOPT])dnl
+  #
+  tst_method="unknown"
+
+  AC_MSG_CHECKING([how to set a socket into non-blocking mode])
+  if test "x$curl_cv_func_fcntl_o_nonblock" = "xyes"; then
+    tst_method="fcntl O_NONBLOCK"
+  elif test "x$curl_cv_func_ioctl_fionbio" = "xyes"; then
+    tst_method="ioctl FIONBIO"
+  elif test "x$curl_cv_func_ioctlsocket_fionbio" = "xyes"; then
+    tst_method="ioctlsocket FIONBIO"
+  elif test "x$curl_cv_func_ioctlsocket_camel_fionbio" = "xyes"; then
+    tst_method="IoctlSocket FIONBIO"
+  elif test "x$curl_cv_func_setsockopt_so_nonblock" = "xyes"; then
+    tst_method="setsockopt SO_NONBLOCK"
+  fi
+  AC_MSG_RESULT([$tst_method])
+  if test "$tst_method" = "unknown"; then
+    AC_MSG_WARN([cannot determine non-blocking socket method.])
+  fi
+])
+
+
+dnl CURL_CONFIGURE_SYMBOL_HIDING
+dnl -------------------------------------------------
+dnl Depending on --enable-symbol-hiding or --disable-symbol-hiding
+dnl configure option, and compiler capability to actually honor such
+dnl option, this will modify compiler flags as appropriate and also
+dnl provide needed definitions for configuration and Makefile.am files.
+dnl This macro should not be used until all compilation tests have
+dnl been done to prevent interferences on other tests.
+
+AC_DEFUN([CURL_CONFIGURE_SYMBOL_HIDING], [
+  AC_MSG_CHECKING([whether hiding of library internal symbols will actually happen])
+  CFLAG_CURL_SYMBOL_HIDING=""
+  doing_symbol_hiding="no"
+  if test x"$curl_cv_native_windows" != "xyes" &&
+    test "$want_symbol_hiding" = "yes" &&
+    test "$supports_symbol_hiding" = "yes"; then
+    doing_symbol_hiding="yes"
+    CFLAG_CURL_SYMBOL_HIDING="$symbol_hiding_CFLAGS"
+    AC_DEFINE_UNQUOTED(CURL_EXTERN_SYMBOL, $symbol_hiding_EXTERN,
+      [Definition to make a library symbol externally visible.])
+    AC_MSG_RESULT([yes])
+  else
+    AC_MSG_RESULT([no])
+  fi
+  AM_CONDITIONAL(DOING_CURL_SYMBOL_HIDING, test x$doing_symbol_hiding = xyes)
+  AC_SUBST(CFLAG_CURL_SYMBOL_HIDING)
+])
+
+
+dnl CURL_CHECK_LIB_ARES
+dnl -------------------------------------------------
+dnl When c-ares library support has been requested,
+dnl performs necessary checks and adjustsments needed
+dnl to enable support of this library.
+
+AC_DEFUN([CURL_CHECK_LIB_ARES], [
+  #
+  if test "$want_ares" = "yes"; then
+    dnl c-ares library support has been requested
+    clean_CPPFLAGS="$CPPFLAGS"
+    clean_LDFLAGS="$LDFLAGS"
+    clean_LIBS="$LIBS"
+    embedded_ares="unknown"
+    configure_runpath=`pwd`
+    embedded_ares_builddir="$configure_runpath/ares"
+    if test -n "$want_ares_path"; then
+      dnl c-ares library path has been specified
+      ARES_PCDIR="$want_ares_path/lib/pkgconfig"
+      CURL_CHECK_PKGCONFIG(libcares, [$ARES_PCDIR])
+      if test "$PKGCONFIG" != "no" ; then
+        ares_LIBS=`CURL_EXPORT_PCDIR([$ARES_PCDIR])
+          $PKGCONFIG --libs-only-l libcares`
+        ares_LDFLAGS=`CURL_EXPORT_PCDIR([$ARES_PCDIR])
+          $PKGCONFIG --libs-only-L libcares`
+        ares_CPPFLAGS=`CURL_EXPORT_PCDIR([$ARES_PCDIR])
+          $PKGCONFIG --cflags-only-I libcares`
+        AC_MSG_NOTICE([pkg-config: ares LIBS: "$ares_LIBS"])
+        AC_MSG_NOTICE([pkg-config: ares LDFLAGS: "$ares_LDFLAGS"])
+        AC_MSG_NOTICE([pkg-config: ares CPPFLAGS: "$ares_CPPFLAGS"])
+      else
+        dnl ... path without pkg-config
+        ares_CPPFLAGS="-I$want_ares_path/include"
+        ares_LDFLAGS="-L$want_ares_path/lib"
+        ares_LIBS="-lcares"
+      fi
+    else
+      dnl c-ares library path has not been given
+      if test -d "$srcdir/ares"; then
+        dnl c-ares sources embedded in curl tree
+        embedded_ares="yes"
+        AC_CONFIG_SUBDIRS(ares)
+        dnl c-ares has installable configured header files, path
+        dnl inclusion fully done in makefiles for in-tree builds.
+        ares_CPPFLAGS=""
+        ares_LDFLAGS="-L$embedded_ares_builddir"
+        ares_LIBS="-lcares"
+      else
+        dnl c-ares path not specified, use defaults
+        CURL_CHECK_PKGCONFIG(libcares)
+        if test "$PKGCONFIG" != "no" ; then
+          ares_LIBS=`$PKGCONFIG --libs-only-l libcares`
+          ares_LDFLAGS=`$PKGCONFIG --libs-only-L libcares`
+          ares_CPPFLAGS=`$PKGCONFIG --cflags-only-I libcares`
+          AC_MSG_NOTICE([pkg-config: ares_LIBS: "$ares_LIBS"])
+          AC_MSG_NOTICE([pkg-config: ares_LDFLAGS: "$ares_LDFLAGS"])
+          AC_MSG_NOTICE([pkg-config: ares_CPPFLAGS: "$ares_CPPFLAGS"])
+        else
+          ares_CPPFLAGS=""
+          ares_LDFLAGS=""
+          ares_LIBS="-lcares"
+        fi
+      fi
+    fi
+    #
+    CPPFLAGS="$clean_CPPFLAGS $ares_CPPFLAGS"
+    LDFLAGS="$clean_LDFLAGS $ares_LDFLAGS"
+    LIBS="$ares_LIBS $clean_LIBS"
+    #
+    if test "$embedded_ares" != "yes"; then
+      dnl check if c-ares new enough when not using an embedded
+      dnl source tree one which normally has not been built yet.
+      AC_MSG_CHECKING([that c-ares is good and recent enough])
+      AC_LINK_IFELSE([
+        AC_LANG_PROGRAM([[
+#include <ares.h>
+          /* set of dummy functions in case c-ares was built with debug */
+          void curl_dofree() { }
+          void curl_sclose() { }
+          void curl_domalloc() { }
+          void curl_docalloc() { }
+          void curl_socket() { }
+        ]],[[
+          ares_channel channel;
+          ares_cancel(channel); /* added in 1.2.0 */
+          ares_process_fd(channel, 0, 0); /* added in 1.4.0 */
+          ares_dup(&channel, channel); /* added in 1.6.0 */
+        ]])
+      ],[
+        AC_MSG_RESULT([yes])
+      ],[
+        AC_MSG_RESULT([no])
+        AC_MSG_ERROR([c-ares library defective or too old])
+        dnl restore initial settings
+        CPPFLAGS="$clean_CPPFLAGS"
+        LDFLAGS="$clean_LDFLAGS"
+        LIBS="$clean_LIBS"
+        # prevent usage
+        want_ares="no"
+      ])
+    fi
+    if test "$want_ares" = "yes"; then
+      dnl finally c-ares will be used
+      AC_DEFINE(USE_ARES, 1, [Define to enable c-ares support])
+      AC_SUBST([USE_ARES], [1])
+      curl_res_msg="c-ares"
+    fi
+  fi
+])
+
+
+dnl CURL_CHECK_OPTION_NTLM_WB
+dnl -------------------------------------------------
+dnl Verify if configure has been invoked with option
+dnl --enable-ntlm-wb or --disable-ntlm-wb, and set
+dnl shell variable want_ntlm_wb and want_ntlm_wb_file
+dnl as appropriate.
+
+AC_DEFUN([CURL_CHECK_OPTION_NTLM_WB], [
+  AC_BEFORE([$0],[CURL_CHECK_NTLM_WB])dnl
+  OPT_NTLM_WB="default"
+  AC_ARG_ENABLE(ntlm-wb,
+AC_HELP_STRING([--enable-ntlm-wb@<:@=FILE@:>@],[Enable NTLM delegation to winbind's ntlm_auth helper, where FILE is ntlm_auth's absolute filename (default: /usr/bin/ntlm_auth)])
+AC_HELP_STRING([--disable-ntlm-wb],[Disable NTLM delegation to winbind's ntlm_auth helper]),
+  OPT_NTLM_WB=$enableval)
+  want_ntlm_wb_file="/usr/bin/ntlm_auth"
+  case "$OPT_NTLM_WB" in
+    no)
+      dnl --disable-ntlm-wb option used
+      want_ntlm_wb="no"
+      ;;
+    default)
+      dnl configure option not specified
+      want_ntlm_wb="yes"
+      ;;
+    *)
+      dnl --enable-ntlm-wb option used
+      want_ntlm_wb="yes"
+      if test -n "$enableval" && test "$enableval" != "yes"; then
+        want_ntlm_wb_file="$enableval"
+      fi
+      ;;
+  esac
+])
+
+
+dnl CURL_CHECK_NTLM_WB
+dnl -------------------------------------------------
+dnl Check if support for NTLM delegation to winbind's
+dnl ntlm_auth helper will finally be enabled depending
+dnl on given configure options and target platform.
+
+AC_DEFUN([CURL_CHECK_NTLM_WB], [
+  AC_REQUIRE([CURL_CHECK_OPTION_NTLM_WB])dnl
+  AC_REQUIRE([CURL_CHECK_NATIVE_WINDOWS])dnl
+  AC_MSG_CHECKING([whether to enable NTLM delegation to winbind's helper])
+  if test "$curl_cv_native_windows" = "yes" ||
+    test "x$SSL_ENABLED" = "x"; then
+    want_ntlm_wb_file=""
+    want_ntlm_wb="no"
+  fi
+  AC_MSG_RESULT([$want_ntlm_wb])
+  if test "$want_ntlm_wb" = "yes"; then
+    AC_DEFINE(NTLM_WB_ENABLED, 1,
+      [Define to enable NTLM delegation to winbind's ntlm_auth helper.])
+    AC_DEFINE_UNQUOTED(NTLM_WB_FILE, "$want_ntlm_wb_file",
+      [Define absolute filename for winbind's ntlm_auth helper.])
+    NTLM_WB_ENABLED=1
+  fi
+])