patch 8.2.2970: Python configure check uses deprecated command

Problem:    Python configure check uses deprecated command.
Solution:   Use sysconfig instead of distutils if possible. (Zdenek Dohnal,
            closes #8354)
diff --git a/src/configure.ac b/src/configure.ac
index 2db0449..9810ea1 100644
--- a/src/configure.ac
+++ b/src/configure.ac
@@ -1487,7 +1487,10 @@
       [
        vi_cv_path_python3_conf=
        config_dir="config-${vi_cv_var_python3_version}${vi_cv_var_python3_abiflags}"
-       d=`${vi_cv_path_python3} -c "import distutils.sysconfig; print(distutils.sysconfig.get_config_var('LIBPL'))"`
+       d=`${vi_cv_path_python3} -c "import sysconfig; print(sysconfig.get_config_var('LIBPL'))" 2> /dev/null`
+       if test "x$d" = "x"; then
+         d=`${vi_cv_path_python3} -c "import distutils.sysconfig; print(distutils.sysconfig.get_config_var('LIBPL'))"`
+       fi
        if test -d "$d" && test -f "$d/config.c"; then
          vi_cv_path_python3_conf="$d"
        else