AC_PATH_TOOL([CURL_CONFIG], [curl-config], No)
   if test ! x"${CURL_CONFIG}" = xNo; then
   # check for version
      if test $(printf "%d" 0x$(${CURL_CONFIG} --vernum)) -ge $(printf "%d" 0x070907); then
         CURL_INCLUDE=$(${CURL_CONFIG} --cflags)
         CURL_LIB=$(${CURL_CONFIG} --libs)

         AC_MSG_CHECKING(for curl_version() in curl/curl.h)
         saved_cppflags="${CPPFLAGS}"
         CPPFLAGS="${CPPFLAGS} ${CURL_INCLUDE}"
         AC_COMPILE_IFELSE(
            [AC_LANG_PROGRAM(
                [#include <curl/curl.h>],
                    [curl_version();])
            ],[
                AC_MSG_RESULT(yes)
                ac_cv_curl_h="yes"
            ],[
                AC_MSG_RESULT(no)
                ac_cv_curl_h="no"
            ]
     )
     CPPFLAGS="${saved_cppflags}"
         if test "${ac_cv_curl_h}" = "yes"; then
             PBX_CURL=1
             AC_DEFINE([HAVE_CURL], 1, [Define if your system has the curl libraries.])
         fi
      fi
   fi