1 files changed, 7 insertions, 3 deletions
diff --git a/iso646.h b/iso646.h
index 2e40179..660625f 100644
--- a/iso646.h
+++ b/iso646.h
@@ -1,5 +1,9 @@
-#ifndef __ISO646_H__
-#define __ISO646_H__
+#ifndef __STDC_VERSION_ISO646_H__
+#if defined __STDC_VERSION__
+#define __STDC_VERSION_ISO646_H__ __STDC_VERSION__
+#else
+#define __STDC_VERSION_ISO646_H__ 1
+#endif
 
 /*
 UNG's Not GNU
@@ -27,7 +31,7 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 */
 
-#if !(defined __STDC_VERSION__ && 199409L <= __STDC_VERSION__)
+#if (__STDC_VERSION_ISO646_H__ < 199409L)
 # error <iso646.h> requires C95 or higher
 #endif