patch 9.0.0859: compiler warning for unused variable

Problem:    Compiler warning for unused variable.
Solution:   Add #ifdef.

src/ex_docmd.c

@@ -4308,8 +4308,9 @@ get_address(
     lnum = MAXLNUM;
     do
     {
+#ifdef FEAT_FOLDING
 	int base_char = *cmd;
-
+#endif
 	switch (*cmd)
 	{
 	    case '.':			    // '.' - Cursor position

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    859,
 /**/
     858,
 /**/