diff --git a/utils/magic.h b/utils/magic.h
index ca9e1eec..eebcd253 100644
--- a/utils/magic.h
+++ b/utils/magic.h
@@ -49,7 +49,13 @@ ERROR: Cannot compile without knowing the size of a pointer.  See utils/magic.h
 typedef int64_t dlong;
 #define DLONG_MAX INT64_MAX
 #define DLONG_MIN INT64_MIN
+#if (defined(__x86_64__) && !defined(_WIN64))
+/* gcc x86_64 defines int64_t as 'long int' on LP64 */
+#define DLONG_PREFIX "l"
+#else
+/* for 32bit and 64bit LLP64 (_WIN64) systems */
 #define DLONG_PREFIX "ll"
+#endif
 
 /* --------------------- Universal pointer type ----------------------- */