patch 8.1.0976: dosinstall still has buffer overflow problems

Problem:    Dosinstall still has buffer overflow problems.
Solution:   Adjust  buffer sizes. (Yasuhiro Matsumoto, closes #4002)
diff --git a/src/version.c b/src/version.c
index 0980420..b747925 100644
--- a/src/version.c
+++ b/src/version.c
@@ -780,6 +780,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    976,
+/**/
     975,
 /**/
     974,