patch 8.2.4968: reading past end of the line when C-indenting

Problem:    Reading past end of the line when C-indenting.
Solution:   Check for NUL.
diff --git a/src/cindent.c b/src/cindent.c
index ec88036..2d47e64 100644
--- a/src/cindent.c
+++ b/src/cindent.c
@@ -89,7 +89,7 @@
 		while (vim_isdigit(p[i - 1]))   // '\000'
 		    ++i;
 	    }
-	    if (p[i] == '\'')		    // check for trailing '
+	    if (p[i - 1] != NUL && p[i] == '\'')    // check for trailing '
 	    {
 		p += i;
 		continue;
diff --git a/src/testdir/test_cindent.vim b/src/testdir/test_cindent.vim
index dbd4aa0..c65a0da 100644
--- a/src/testdir/test_cindent.vim
+++ b/src/testdir/test_cindent.vim
@@ -5319,6 +5319,13 @@
   close!
 endfunc
 
+" This was reading past the end of the line
+func Test_cindent_check_funcdecl()
+  new
+  sil norm o0('\0=L
+  bwipe!
+endfunc
+
 func Test_cindent_scopedecls()
   new
   setl cindent ts=4 sw=4
diff --git a/src/version.c b/src/version.c
index 6359e03..7397e6f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4968,
+/**/
     4967,
 /**/
     4966,