Fix up IPv6 support, and remove remaining dirent checks.

Fix up IPv6 support, and remove remaining dirent checks.

backend/lpd.c:
    - lpd_queue(): Use http_addr_t, httpAddrLoad(), and loop
      through addresses.

backend/socket.c:
    - main(): Use http_addr_t, httpAddrLoad(), and loop through
      addresses.

config.h.in:
    - Add HAVE_GETADDRINFO.
    - Replace HAVE_RRESVPORT with HAVE_RRESVPORT_AF.
    - Remove dirent defines.

config-scripts/cups-common.m4:
    - Remove AC_DIRENT.

config-scripts/cups-network.m4:
    - Add check for getaddrinfo.
    - Replace check for rresvport with check for rresvport_af.

cups/http.c:
    - httpConnect(): Change "encrypt" to "encryption".
    - httpConnectEncrypt(): Change "encrypt" to "encryption".

cups/http.h:
    - httpConnectEncrypt(): Change "encrypt" to "encryption".

cups/http-addr.c:
    - httpAddrLocalhost(): Treat unspecified IPv6 address as
      local.
    - httpAddrString(): Change IPv6 address format to [x:x:x:x].
    - httpAddrGetHostByName(): Support [x:x:x:x] format for IPv6
      addresses and use getaddrinfo() if available.

cups/http-support.c:
    - httpSeparate(): Change method to scheme.
    - httpSeparate2(): Change method to scheme, methodlen to
      schemelen, support IPv6 addresses using the [x:x:x:x]
      format, and decode all resources for the shortcut forms.

pdftops/gfile.h:
    - Remove DIRENT checks.

scheduler/auth.c:
    - CheckAuth(): Make IPv6 variables conditional.
    - cupsdIsAuthorized(): Load IPv4 address using 0:0:0 prefix.

scheduler/client.c:
    - AcceptClient(): Only do lookup after checking localhost and
      server address.

scheduler/conf.c:
    - get_address(): Support [x:x:x:x] format for IPv6 addresses,
      and load IPv4 addresses using 0:0:0 prefix.
    - get_addr_and_mask(): Support [x:x:x:x] format for IPv6 addresses,
      and load IPv4 addresses using 0:0:0 prefix.
    - read_configuration(): Add experimental code to double up
      IPv6 + IPv4 for wildcard address (commented, since it isn't
      needed for Linux, but we need to test other OS's...)

scheduler/listen.c:
    - StartListening(): Automatically try binding IPv4 versions
      of IPv6 loopback and "any" addresses, in case the local
      system does not have IPv6 enabled at run time.

git-svn-id: svn+ssh://src.apple.com/svn/cups/cups.org/trunk@4653 7a7537e8-13f0-0310-91df-b6672ffda945