[BUILD] add -fno-strict-aliasing to fix warnings with gcc >= 4.4

[BUILD] add -fno-strict-aliasing to fix warnings with gcc >= 4.4

Gcc 4.4 enables strict aliasing by default, resuling in complaints
when casting struct sockaddr_storage to sockaddr_in. Not only doing
this does not provide any noticeable performance improvement, it also
presents a risk of strange bugs even when the compiler does not emit
a warning, so let's disable this optimization !