check for getifaddrs and freeifaddrs as it is done for other functions

configure.ac

@@ -2016,11 +2016,13 @@ CURL_CHECK_MSG_NOSIGNAL
 CURL_CHECK_FUNC_ALARM
 CURL_CHECK_FUNC_FDOPEN
 CURL_CHECK_FUNC_FREEADDRINFO
+CURL_CHECK_FUNC_FREEIFADDRS
 CURL_CHECK_FUNC_FTRUNCATE
 CURL_CHECK_FUNC_GETADDRINFO
 CURL_CHECK_FUNC_GETHOSTBYADDR_R
 CURL_CHECK_FUNC_GETHOSTBYNAME_R
 CURL_CHECK_FUNC_GETHOSTNAME
+CURL_CHECK_FUNC_GETIFADDRS
 CURL_CHECK_FUNC_GETSERVBYPORT_R
 CURL_CHECK_FUNC_GMTIME_R
 CURL_CHECK_FUNC_INET_NTOA_R
@@ -2063,7 +2065,6 @@ AC_CHECK_FUNCS([basename \
   fork \
   geteuid \
   gethostbyaddr \
-  getifaddrs \
   getpass_r \
   getppid \
   getprotobyname \

m4/curl-functions.m4

@@ -22,7 +22,7 @@
 #***************************************************************************
 
 # File version for 'aclocal' use. Keep it a single number.
-# serial 33
+# serial 34
 
 
 dnl CURL_INCLUDES_ARPA_INET
@@ -52,6 +52,33 @@ curl_includes_arpa_inet="\
 ])
 
 
+dnl CURL_INCLUDES_IFADDRS
+dnl -------------------------------------------------
+dnl Set up variable with list of headers that must be
+dnl included when ifaddrs.h is to be included.
+
+AC_DEFUN([CURL_INCLUDES_IFADDRS], [
+curl_includes_ifaddrs="\
+/* includes start */
+#ifdef HAVE_SYS_TYPES_H
+#  include <sys/types.h>
+#endif
+#ifdef HAVE_SYS_SOCKET_H
+#  include <sys/socket.h>
+#endif
+#ifdef HAVE_NETINET_IN_H
+#  include <netinet/in.h>
+#endif
+#ifdef HAVE_IFADDRS_H
+#  include <ifaddrs.h>
+#endif
+/* includes end */"
+  AC_CHECK_HEADERS(
+    sys/types.h sys/socket.h netinet/in.h ifaddrs.h,
+    [], [], [$curl_includes_ifaddrs])
+])
+
+
 dnl CURL_INCLUDES_NETDB
 dnl -------------------------------------------------
 dnl Set up variable with list of headers that must be
@@ -594,6 +621,90 @@ AC_DEFUN([CURL_CHECK_FUNC_FREEADDRINFO], [
 ])
 
 
+dnl CURL_CHECK_FUNC_FREEIFADDRS
+dnl -------------------------------------------------
+dnl Verify if freeifaddrs is available, prototyped, and
+dnl can be compiled. If all of these are true, and
+dnl usage has not been previously disallowed with
+dnl shell variable curl_disallow_freeifaddrs, then
+dnl HAVE_FREEIFADDRS will be defined.
+
+AC_DEFUN([CURL_CHECK_FUNC_FREEIFADDRS], [
+  AC_REQUIRE([CURL_INCLUDES_IFADDRS])dnl
+  #
+  tst_links_freeifaddrs="unknown"
+  tst_proto_freeifaddrs="unknown"
+  tst_compi_freeifaddrs="unknown"
+  tst_allow_freeifaddrs="unknown"
+  #
+  AC_MSG_CHECKING([if freeifaddrs can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([freeifaddrs])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_freeifaddrs="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_freeifaddrs="no"
+  ])
+  #
+  if test "$tst_links_freeifaddrs" = "yes"; then
+    AC_MSG_CHECKING([if freeifaddrs is prototyped])
+    AC_EGREP_CPP([freeifaddrs],[
+      $curl_includes_ifaddrs
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_freeifaddrs="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_freeifaddrs="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_freeifaddrs" = "yes"; then
+    AC_MSG_CHECKING([if freeifaddrs is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $curl_includes_ifaddrs
+      ]],[[
+        freeifaddrs(0);
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_freeifaddrs="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_freeifaddrs="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_freeifaddrs" = "yes"; then
+    AC_MSG_CHECKING([if freeifaddrs usage allowed])
+    if test "x$curl_disallow_freeifaddrs" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_freeifaddrs="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_freeifaddrs="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if freeifaddrs might be used])
+  if test "$tst_links_freeifaddrs" = "yes" &&
+     test "$tst_proto_freeifaddrs" = "yes" &&
+     test "$tst_compi_freeifaddrs" = "yes" &&
+     test "$tst_allow_freeifaddrs" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_FREEIFADDRS, 1,
+      [Define to 1 if you have the freeifaddrs function.])
+    ac_cv_func_freeifaddrs="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_freeifaddrs="no"
+  fi
+])
+
+
 dnl CURL_CHECK_FUNC_FTRUNCATE
 dnl -------------------------------------------------
 dnl Verify if ftruncate is available, prototyped, and
@@ -1193,6 +1304,120 @@ AC_DEFUN([CURL_CHECK_FUNC_GETHOSTNAME], [
 ])
 
 
+dnl CURL_CHECK_FUNC_GETIFADDRS
+dnl -------------------------------------------------
+dnl Verify if getifaddrs is available, prototyped, can
+dnl be compiled and seems to work. If all of these are
+dnl true, and usage has not been previously disallowed
+dnl with shell variable curl_disallow_getifaddrs, then
+dnl HAVE_GETIFADDRS will be defined.
+
+AC_DEFUN([CURL_CHECK_FUNC_GETIFADDRS], [
+  AC_REQUIRE([CURL_INCLUDES_IFADDRS])dnl
+  #
+  tst_links_getifaddrs="unknown"
+  tst_proto_getifaddrs="unknown"
+  tst_compi_getifaddrs="unknown"
+  tst_works_getifaddrs="unknown"
+  tst_allow_getifaddrs="unknown"
+  #
+  AC_MSG_CHECKING([if getifaddrs can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([getifaddrs])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_getifaddrs="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_getifaddrs="no"
+  ])
+  #
+  if test "$tst_links_getifaddrs" = "yes"; then
+    AC_MSG_CHECKING([if getifaddrs is prototyped])
+    AC_EGREP_CPP([getifaddrs],[
+      $curl_includes_ifaddrs
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_getifaddrs="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_getifaddrs="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_getifaddrs" = "yes"; then
+    AC_MSG_CHECKING([if getifaddrs is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $curl_includes_ifaddrs
+      ]],[[
+        if(0 != getifaddrs(0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_getifaddrs="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_getifaddrs="no"
+    ])
+  fi
+  #
+  dnl only do runtime verification when not cross-compiling
+  if test "x$cross_compiling" != "xyes" &&
+    test "$tst_compi_getifaddrs" = "yes"; then
+    AC_MSG_CHECKING([if getifaddrs seems to work])
+    AC_RUN_IFELSE([
+      AC_LANG_PROGRAM([[
+        $curl_includes_ifaddrs
+      ]],[[
+        struct ifaddrs *ifa = 0;
+        int error;
+
+        error = getifaddrs(&ifa);
+        if(error || !ifa)
+          exit(1); /* fail */
+        else
+          exit(0);
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_works_getifaddrs="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_works_getifaddrs="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_getifaddrs" = "yes" &&
+    test "$tst_works_getifaddrs" != "no"; then
+    AC_MSG_CHECKING([if getifaddrs usage allowed])
+    if test "x$curl_disallow_getifaddrs" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_getifaddrs="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_getifaddrs="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if getifaddrs might be used])
+  if test "$tst_links_getifaddrs" = "yes" &&
+     test "$tst_proto_getifaddrs" = "yes" &&
+     test "$tst_compi_getifaddrs" = "yes" &&
+     test "$tst_allow_getifaddrs" = "yes" &&
+     test "$tst_works_getifaddrs" != "no"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_GETIFADDRS, 1,
+      [Define to 1 if you have a working getifaddrs function.])
+    ac_cv_func_getifaddrs="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_getifaddrs="no"
+  fi
+])
+
+
 dnl CURL_CHECK_FUNC_GETSERVBYPORT_R
 dnl -------------------------------------------------
 dnl Verify if getservbyport_r is available, prototyped,