Well, I believe that GCC is trying to tell you that snprintf does not have the return type that GCC thinks it should have. I tried to reproduce this locally but could not. If GCC were seeing two conflicting declarations for snprintf, it should give the location of each. Since it doesn't I think that GCC is saying that the definition it does see is not what it expects based on an internal table of known functions that it has. Can you look at /usr/local/lib/gcc/ia64-hp-hpux11.23/4.0.2/include/stdio.h and find the declaration of snprintf and tell us what it is? It should be declared an int function. It might also be useful to look at /usr/include/stdio.h and find the declaration of snprintf there and see if it is different.
The reason this is an error, of course, is your use of -Werror which turns warnings into errors. But I assume you want this flag because you are specifically using GCC for error checking your code.
Also, was this version of GCC downloaded from somewhere or did you build it yourself? Knowning where it came from might help figure out what is going on.
