add -fno-strict-aliasing to the gcc compiler flags. this is needed, see:
http://www.exim.org/mail-archives/exim-users/Week-of-Mon-
20030721/msg00141.html
| It's not a compiler bug. It is a C99 bug, or more exactly, a
| feature. C99 changed the semantic of the C language with respect to
| aliasing questions. Now, the compiler can assume that pointer to
| different types points to different memory location. This breaks all
| the OO code written in C.
|
| This is a very good idea that the compiler issues a warning message
| because the semantic of language really changed and you want to revert
| to the old semantic.
|
| The make package MUST add -fno-strict-aliasing. It is not a
| convenience to get rid off warnings.