[evolution-patches] Fixes for compiler warnings about signedness

[Kjartan Maraas <kmaraas broadpark no>]

Hi.

Lately I've tried to fix compiler warnings in evolution and it's
dependencies and I've gotten to the point where most of the remaining
ones are of this type:

e-account.c:150: warning: pointer targets in passing argument 2 of 'xmlGetProp' differ in signedness
e2k-result.c:126: warning: pointer targets in assignment differ in signedness

etc.

I wonder if there's consensus on how to tackle these warnings that were
introduced somewhere around GCC 3.3 or something. I hear arguments
ranging from "ignore them", "make the compiler not issue them", "use
casts to quiet the compiler", "use casts to make sure we maintain type
correctness", "gcc sucks" etc.

Most of these warnings also show up when compiling with Intel's compiler
so I guess the argument that GCC sucks isn't exactly the best. Also some
developers go as far as saying that this in fact is code that could be
rejected as non-compliant by the compiler in the future...

I'd like to get some thoughts from others to see how we can get rid of
these in a sensible manner.

Cheers
Kjartan