Doubled slash instead of simple slash when running makeinfo v4.13

[Christophe Jarry]

Hello,

When i want to "makeinfo" the "gnu.texi" file in the latest version of
GCC documentation file at 
http://gcc.gnu.org/onlinedocs/gcc-4.4.2/docs-sources.tar.gz (at
gcc/gcc/doc/), i have this error:

$ makeinfo --version && makeinfo gnu.texi
makeinfo (GNU texinfo) 4.13

Copyright (C) 2008 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later
<http://gnu.org/licenses/gpl.html> This is free software: you are free
to change and redistribute it. There is NO WARRANTY, to the extent
permitted by law. /tmp/gcc/gcc/doc//gnu.texi:5: `GNU Project' has no Up
field (perhaps incorrect sectioning?). /tmp/gcc/gcc/doc//gnu.texi:5:
warning: unreferenced node `GNU Project'. makeinfo: Removing output
file `gnu.info' due to errors; use --force to preserve.

So here are simple slash "/" replaced by double ones "//", is that a
bug?

Christophe