Compile fails on Windows due to __null being some reserved keyword

[stephanj]

mingw on windows complains about a reserved keyword it seems.

$ gcc --version
gcc.exe (GCC) 4.6.1
Copyright (C) 2011 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

a quickfix discussed on irc helped:

$ diff uuid.c  current/libroar/uuid.c
88c88
<  static const roar_uuid_t * __null = NULL,
---
>  static const roar_uuid_t * nix = NULL,
96c96
<   return __null;
---
>   return nix;
110c110
<  return __null;
---
>  return nix;