[libxml2] Disable FTP support by default

[Nick Wellnhofer <nwellnhof src gnome org>]

commit a0a0f3be93753e387e31e7de95904a24b3c876dd
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Sun Feb 20 17:33:47 2022 +0100

    Disable FTP support by default
    
    In the unlikely case that you really need FTP support, you have to
    enable it explicitly with:
    
        ./configure --with-ftp

 configure.ac | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 46faa236..5e84c910 100644
--- a/configure.ac
+++ b/configure.ac
@@ -102,7 +102,7 @@ AC_ARG_WITH(docbook,
 AC_ARG_WITH(fexceptions,
 [  --with-fexceptions      add GCC flag -fexceptions for C++ exceptions (off)])
 AC_ARG_WITH(ftp,
-[  --with-ftp              add the FTP support (on)])
+[  --with-ftp              add the FTP support (off)])
 AC_ARG_WITH(history,
 [  --with-history          add history support to xmllint shell(off)])
 AC_ARG_WITH(html,
@@ -254,10 +254,6 @@ then
     then
       with_fexceptions=no
     fi
-    if test "$with_ftp" = ""
-    then
-      with_ftp=no 
-    fi
     if test "$with_history" = ""
     then
       with_history=no
@@ -1128,7 +1124,7 @@ else
 fi
 AC_SUBST(WITH_TREE)
 
-if test "$with_ftp" = "no" ; then
+if test "$with_ftp" != "yes" ; then
     echo Disabling FTP support
     WITH_FTP=0
     FTP_OBJ=