fixinc required for new FreeBSD 4.x bootstrap failures

[Vladimir Merzliakov]

> FreeBSD 4.x has constructs of the following kind in system headers like 
> /usr/include/stdlib.h:
>
>   int      abs __P((int)) __pure2;
>
> where /usr/include/sys/cdefs.h has the following definitions

Note:
Related GCC bug report : http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17434 
(now closed)
Bug report to FreeBSD http://www.freebsd.org/cgi/query-pr.cgi?pr=71675

Vladimir