patch 9.0.1427: warning for uninitialized variable

Problem:    Warning for uninitialized variable. (Tony Mechelynck)
Solution:   Add #ifdef.
diff --git a/src/regexp_nfa.c b/src/regexp_nfa.c
index cc29a4c..406a0e4 100644
--- a/src/regexp_nfa.c
+++ b/src/regexp_nfa.c
@@ -6678,7 +6678,9 @@
 		int subidx;
 		int bytelen;
 
-		if (t->state->c <= NFA_BACKREF9)
+#ifdef FEAT_SYN_HL
+		if (t->state->c >= NFA_BACKREF1 && t->state->c <= NFA_BACKREF9)
+#endif
 		{
 		    subidx = t->state->c - NFA_BACKREF1 + 1;
 		    result = match_backref(&t->subs.norm, subidx, &bytelen);
diff --git a/src/version.c b/src/version.c
index f44e29c..0a4a8a0 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1427,
+/**/
     1426,
 /**/
     1425,