patch 9.0.0761: cannot use 'indentexpr' for Lisp indenting

Problem:    Cannot use 'indentexpr' for Lisp indenting.
Solution:   Add the 'lispoptions' option.
diff --git a/src/option.h b/src/option.h
index 6d05f0e..e266d38 100644
--- a/src/option.h
+++ b/src/option.h
@@ -709,6 +709,7 @@
 EXTERN long	p_linespace;	// 'linespace'
 #endif
 EXTERN int	p_lisp;		// 'lisp'
+EXTERN char_u	*p_lop;		// 'lispoptions'
 EXTERN char_u	*p_lispwords;	// 'lispwords'
 EXTERN long	p_ls;		// 'laststatus'
 EXTERN long	p_stal;		// 'showtabline'
@@ -1155,6 +1156,7 @@
 #endif
     , BV_KP
     , BV_LISP
+    , BV_LOP
     , BV_LW
     , BV_MENC
     , BV_MA