ibrdtn: new package

[Thomas:
  - Add missing include in package/Config.in to make the package
    appear in menuconfig.
  - Fix the comment dependencies: the comment should be shown either
    if C++ is not available *or* if threads are not supported.
  - Add a hash file.
  - Add missing dependency on host-pkgconf, since pkg-config is used
    to detect the availability of ibrcommon.
  - Remove the custom INSTALL_STAGING_OPTS and INSTALL_TARGET_OPTS:
    they are not needed since automake is used.
  - Make --with-compression conditional on whether zlib is available.
  - Add optional dependency on libglib2.
  - Add missing final newlines in .mk and Config.in files.]

Signed-off-by: Tom Sparks <tom_a_sparks@yahoo.com.au>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>