[coretext] Fix build

error: static_assert expression is not an integral constant expression

src/hb-coretext.cc

diff --git a/src/hb-coretext.cc b/src/hb-coretext.cc
index ca54833..937822b 100644
--- a/src/hb-coretext.cc
+++ b/src/hb-coretext.cc
@@ -678,7 +678,7 @@
 	      CFNumberCreate (kCFAllocatorDefault, kCFNumberIntType, &active_features[j].rec.feature),
 	      CFNumberCreate (kCFAllocatorDefault, kCFNumberIntType, &active_features[j].rec.setting)
 	    };
-	    static_assert ((ARRAY_LENGTH (keys) == ARRAY_LENGTH (values)), "");
+	    static_assert ((ARRAY_LENGTH_CONST (keys) == ARRAY_LENGTH_CONST (values)), "");
 	    CFDictionaryRef dict = CFDictionaryCreate (kCFAllocatorDefault,
 						       (const void **) keys,
 						       (const void **) values,