diff --git a/lib/hcrypto/evp.c b/lib/hcrypto/evp.c
index 70eab2ef9..57c954dbf 100644
--- a/lib/hcrypto/evp.c
+++ b/lib/hcrypto/evp.c
@@ -44,7 +44,7 @@
 #include <evp.h>
 #include <evp-hcrypto.h>
 #include <evp-cc.h>
-#if _WIN32
+#if defined(_WIN32)
 #include <evp-w32.h>
 #endif
 #include <evp-pkcs11.h>
diff --git a/lib/hcrypto/test_bulk.c b/lib/hcrypto/test_bulk.c
index 3d5efe910..e3737fd1e 100644
--- a/lib/hcrypto/test_bulk.c
+++ b/lib/hcrypto/test_bulk.c
@@ -39,7 +39,7 @@
 #include <evp.h>
 #include <evp-hcrypto.h>
 #include <evp-cc.h>
-#if _WIN32
+#if defined(_WIN32)
 #include <evp-w32.h>
 #endif
 #include <evp-pkcs11.h>
diff --git a/lib/hcrypto/test_cipher.c b/lib/hcrypto/test_cipher.c
index b6b6c169a..0131e148b 100644
--- a/lib/hcrypto/test_cipher.c
+++ b/lib/hcrypto/test_cipher.c
@@ -41,7 +41,7 @@
 #include <evp.h>
 #include <evp-hcrypto.h>
 #include <evp-cc.h>
-#if _WIN32
+#if defined(_WIN32)
 #include <evp-w32.h>
 #endif
 #include <evp-pkcs11.h>