Don't use extended attributes (--xattr) by default

* src/init.c (defaults): Set enable_xattr to false by default
* src/main.c (print_help): Reverse option logic of --xattr
* doc/wget.texi: Add description for --xattr

Users may not be aware that the origin URL and Referer are saved
including credentials, and possibly access tokens within
the urls.

doc/wget.texi

@@ -540,6 +540,14 @@ right NUMBER.
 Set preferred location for Metalink resources. This has effect if multiple
 resources with same priority are available.
 
+@cindex xattr
+@item --xattr
+Enable use of file system's extended attributes to save the
+original URL and the Referer HTTP header value if used.
+
+Be aware that the URL might contain private information like
+access tokens or credentials.
+
 
 @cindex force html
 @item -F

src/init.c

@@ -507,11 +507,7 @@ defaults (void)
   opt.hsts = true;
 #endif
 
-#ifdef ENABLE_XATTR
-  opt.enable_xattr = true;
-#else
   opt.enable_xattr = false;
-#endif
 }
 
 /* Return the user's home directory (strdup-ed), or NULL if none is

src/main.c

@@ -755,7 +755,7 @@ Download:\n"),
 #endif
 #ifdef ENABLE_XATTR
     N_("\
-       --no-xattr                  turn off storage of metadata in extended file attributes\n"),
+       --xattr                     turn on storage of metadata in extended file attributes\n"),
 #endif
     "\n",