LibC::Passwd is missing fields on FreeBSD

[dmgk]

As currently defined, LibC::Passwd

crystal/src/lib_c/x86_64-freebsd/c/pwd.cr

Lines 2 to 10 in ee8fca2

	struct Passwd
	pw_name : Char*
	pw_passwd : Char*
	pw_uid : UidT
	pw_gid : GidT
	pw_gecos : Char*
	pw_dir : Char*
	pw_shell : Char*
	end

is currently missing a few fields, which leads to getpwnam_r and getpwuid_r returning wrong data and causes spec/std/path_spec.cr to fail on FreeBSD:

Path .home doesn't return empty string if environment variable is empty
     Failure/Error: Path.home.should_not eq(Path.new(""))

       Expected: actual_value != Path[""]
            got: Path[""]

     # spec/std/path_spec.cr:947