patch 8.1.0730: compiler warning for get_buf_arg() unused

Problem:    Compiler warning for get_buf_arg() unused.
Solution:   Add #ifdef. (John Marriott)

src/evalfunc.c

@@ -1919,6 +1919,7 @@ tv_get_buf(typval_T *tv, int curtab_only)
     return buf;
 }
 
+#ifdef FEAT_SIGNS
 /*
  * Get the buffer from "arg" and give an error and return NULL if it is not
  * valid.
@@ -1935,6 +1936,7 @@ get_buf_arg(typval_T *arg)
 	EMSG2(_("E158: Invalid buffer name: %s"), tv_get_string(arg));
     return buf;
 }
+#endif
 
 /*
  * "bufname(expr)" function

src/version.c

@@ -795,6 +795,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    730,
 /**/
     729,
 /**/