Use sizeof
Updated some required packages for Debian build

With newer version of Debian (Jessie) or Ubuntu (Trusty), the packages
libjson0{,-dev} are transitional packages. Prefer their replacements if
they're available.
Merge pull request #713 from qnet-herwin/debian_json_packages

Updated some required packages for Debian build
Define __APPLE_USER_RFC_2292 so the IPv6 socket options are exposed on OSX
Set errno appropriately if we're building without IPv6 support and an IPv6 socket is requested
Remove redundant includes of netinet/in.h
Pass2 for attributes in existence checks

	if (&foo-LDAP-Group) {
		...
	}