diff --git a/physfs_byteorder.c b/physfs_byteorder.c
index 9e8273d..ec50c26 100644
--- a/physfs_byteorder.c
+++ b/physfs_byteorder.c
@@ -28,6 +28,7 @@
      defined(__arm__) || \
     (defined(__mips__) && defined(__MIPSEL__)) || \
      defined(__SYMBIAN32__) || \
+     defined(__x86_64__) || \
      defined(__LITTLE_ENDIAN__)
 #define PHYSFS_BYTEORDER    PHYSFS_LIL_ENDIAN
 #else