use of %n in genmodes.c causes trouble on Vista

[Olivier Hainque]

Hello,

genmodes.c uses the %n capabilities of printf to compute the width of
pieces it outputs. This causes troubles on Windows Vista, because ...

   << Because of security reasons, support for the %n format specifier is
      disabled by default in printf and all its variants. ... the default
      behavior is to invoke the invalid parameter handler ...
   >>
   [http://msdn2.microsoft.com/en-us/library/ms175782%28VS.80%29.aspx]

It seems to me that we could replace the uses of %n by uses of printf
return values. I'm not clear whether this would be considered portable
enough, however.

Opinions ?

Thanks in advance,

Olivier