patch 7.4.1869

Problem:    Can't build with old version of Perl.
Solution:   Define PERLIO_FUNCS_DECL. (Tom G. Christensen)

src/version.c

@@ -753,6 +753,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1869,
 /**/
     1868,
 /**/