[Bug c/47901] -Wall should not imply -Wformat-zero-length by default

[manu at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47901

--- Comment #3 from Manuel López-Ibáñez <manu at gcc dot gnu.org> 2012-04-23 20:08:09 UTC ---
Well, I don't really see how custom_printf("") can produce any damage. It may
be an oversight when one actually wanted to print something, but it may be as
likely that one didn't want to print something and just trigger some side
effect of custom_printf.

As an alternative, the warning could suggest to use ("%s", "") to silence the
warning, no?