diff --git a/crypto/arm_arch.h b/crypto/arm_arch.h
index 547ec9582708b419091680f6312a569bb3c6d156..f11b543df64f0ca5edbff10eff5cda19c8c1e571 100644
--- a/crypto/arm_arch.h
+++ b/crypto/arm_arch.h
@@ -69,7 +69,7 @@
 #  endif
 # endif
 
-# if !__ASSEMBLER__
+# ifndef __ASSEMBLER__
 extern unsigned int OPENSSL_armcap_P;
 # endif