patch 8.2.5151: reading beyond the end of the line with lisp indenting

Problem:    Reading beyond the end of the line with lisp indenting.
Solution:   Avoid going over the NUL at the end of the line.

src/indent.c

@@ -2076,8 +2076,11 @@ get_lisp_indent(void)
 		    amount += 2;
 		else
 		{
-		    that++;
+		    if (*that != NUL)
-		    amount++;
+		    {
+			that++;
+			amount++;
+		    }
 		    firsttry = amount;
 
 		    while (VIM_ISWHITE(*that))

src/testdir/test_lispwords.vim

@@ -1,4 +1,5 @@
-" Tests for 'lispwords' settings being global-local
+" Tests for 'lispwords' settings being global-local.
+" And  other lisp indent stuff.
 
 set nocompatible viminfo+=nviminfo
 
@@ -85,4 +86,13 @@ func Test_lisp_indent()
   set nolisp
 endfunc
 
+func Test_lisp_indent_works()
+  " This was reading beyond the end of the line
+  new
+  exe "norm a\tü(\<CR>="
+  set lisp
+  norm ==
+  bwipe!
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab

src/version.c

@@ -734,6 +734,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    5151,
 /**/
     5150,
 /**/