patch 8.1.1827: allocating more memory than needed for extended structs

Problem:    Allocating more memory than needed for extended structs.
Solution:   Use offsetof() instead of sizeof(). (Dominique Pelle,
            closes #4786)
diff --git a/src/version.c b/src/version.c
index 93b8a2d..4f8f152 100644
--- a/src/version.c
+++ b/src/version.c
@@ -770,6 +770,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1827,
+/**/
     1826,
 /**/
     1825,