Add two new configure flags:
    --enable-gcc-hardening
        This turns on gcc compile time hardening options. It ensures that
        signed ints have defined behavior (-fwrapv), -D_FORTIFY_SOURCE=2 is
        enabled (requiring -O2), stack smashing protection with canaries
        (-fstack-protector-all), ASLR protection if supported by the kernel
        (-fPIE, -pie). Additional security related warnings are enabled.
        Verified as working on Mac OS X and Debian Lenny.

    --enable-linker-hardening
        This turns on ELF specific hardening features (relro, now). This does
        not work with Mac OS X or any other non-ELF binary format.
