* Disable deprecated function usage errors
 * Don't use 'true' as an identifier name
 * Remove buffer overflow warning.

Make sure we define our socket name length with the correct
type a socklen_t. Should fix this sort of error:

    ../common/spio.c:124:45: error: passing argument 3 of ‘getsockname’ from incompatible pointer type [-Wincompatible-pointer-types]

Glibc and Linux kernel both contain duplicate definitions of structures
like struct sockaddr_in leading to:

    /usr/include/netinet/in.h:31:8: error: redefinition of ‘struct in_addr’
    In file included from /usr/include/linux/netfilter.h:7,
                     from /usr/include/linux/netfilter_ipv4.h:9,
                     from ../common/smtppass.c:64:
    /usr/include/linux/in.h:94:8: note: originally defined here

But we do need to include the linux netfilter definitinos here. Changing
the order seems to help

This copies the last version of the 1.10 clamsmtp common/
files into this project. They used to be shared with the proxsmtp
project but that project has since diverged.