configure: fix recvfrom 5th arg type qualifier detection

acinclude.m4

@@ -1663,7 +1663,7 @@ AC_DEFUN([CURL_CHECK_FUNC_RECVFROM], [
           for recvfrom_arg2 in 'char *' 'void *'; do
             for recvfrom_arg3 in 'size_t' 'int' 'socklen_t' 'unsigned int'; do
               for recvfrom_arg4 in 'int' 'unsigned int'; do
-                for recvfrom_arg5 in 'const struct sockaddr *' 'struct sockaddr *' 'void *'; do
+                for recvfrom_arg5 in 'struct sockaddr *' 'void *' 'const struct sockaddr *'; do
                   for recvfrom_arg6 in 'socklen_t *' 'int *' 'unsigned int *' 'size_t *' 'void *'; do
                     if test "$curl_cv_func_recvfrom_args" = "unknown"; then
                       AC_COMPILE_IFELSE([
@@ -1731,7 +1731,7 @@ AC_DEFUN([CURL_CHECK_FUNC_RECVFROM], [
       shift
       #
       recvfrom_ptrt_arg2=$[2]
-      recvfrom_ptrt_arg5=$[5]
+      recvfrom_qual_type_arg5=$[5]
       recvfrom_ptrt_arg6=$[6]
       #
       AC_DEFINE_UNQUOTED(RECVFROM_TYPE_ARG1, $[1],
@@ -1753,12 +1753,25 @@ AC_DEFUN([CURL_CHECK_FUNC_RECVFROM], [
           ;;
       esac
       #
+      case "$recvfrom_qual_type_arg5" in
+        const*)
+          recvfrom_qual_arg5=const
+          recvfrom_ptrt_arg5=`echo $recvfrom_qual_type_arg5 | sed 's/^const //'`
+        ;;
+        *)
+          recvfrom_qual_arg5=
+          recvfrom_ptrt_arg5=$recvfrom_qual_type_arg5
+        ;;
+      esac
+      #
       recvfrom_type_arg2=`echo $recvfrom_ptrt_arg2 | sed 's/ \*//'`
       recvfrom_type_arg5=`echo $recvfrom_ptrt_arg5 | sed 's/ \*//'`
       recvfrom_type_arg6=`echo $recvfrom_ptrt_arg6 | sed 's/ \*//'`
       #
       AC_DEFINE_UNQUOTED(RECVFROM_TYPE_ARG2, $recvfrom_type_arg2,
         [Define to the type pointed by arg 2 for recvfrom.])
+      AC_DEFINE_UNQUOTED(RECVFROM_QUAL_ARG5, $recvfrom_qual_arg5,
+        [Define to the type qualifier pointed by arg 5 for recvfrom.])
       AC_DEFINE_UNQUOTED(RECVFROM_TYPE_ARG5, $recvfrom_type_arg5,
         [Define to the type pointed by arg 5 for recvfrom.])
       AC_DEFINE_UNQUOTED(RECVFROM_TYPE_ARG6, $recvfrom_type_arg6,