diff -Naur mtools-3.9.9/llong.h mtools-3.9.9-64bit/llong.h
--- mtools-3.9.9/llong.h	2004-02-27 08:42:53.000000000 -0600
+++ mtools-3.9.9-64bit/llong.h	2004-02-27 08:43:09.000000000 -0600
@@ -8,7 +8,7 @@
 /* if off_t is already 64 bits, be happy, and don't worry about the
  * loff_t and llseek stuff */
 #define MT_OFF_T off_t
-#define MT_OFF_T size_t
+#define MT_SIZE_T size_t
 #endif
 
 #ifndef MT_OFF_T