diff -up nvidia-texture-tools/src/nvcore/DefsGnucLinux.h.orig nvidia-texture-tools/src/nvcore/DefsGnucLinux.h
--- nvidia-texture-tools/src/nvcore/DefsGnucLinux.h.orig	2012-05-18 22:17:43.367822764 -0300
+++ nvidia-texture-tools/src/nvcore/DefsGnucLinux.h	2012-05-18 22:19:50.709827759 -0300
@@ -2,6 +2,8 @@
 #error "Do not include this file directly."
 #endif
 
+#include <bits/wordsize.h>
+
 // Function linkage
 #define DLL_IMPORT
 #if __GNUC__ >= 4
@@ -58,8 +60,13 @@ typedef signed short        int16;
 typedef unsigned int        uint32;
 typedef signed int          int32;
 
+#if __WORDSIZE == 32
 typedef unsigned long long  uint64;
 typedef signed long long    int64;
+#else
+typedef unsigned long       uint64;
+typedef signed long         int64;
+#endif
 
 // Aliases
 typedef uint32              uint;