c++: Fix build with clang

c++: Fix build with clang

After the addition of libcody building with clang 10.0.1 would fail
as follows:

  In file included from .../libcody/cody.hh:24:
  In file included from /usr/include/c++/v1/memory:653:
  /usr/include/c++/v1/typeinfo:346:5: error: no member named 'fancy_abort'
  in namespace 'std::__1'; did you mean simply 'fancy_abort'?
    _VSTD::abort();
    ^~~~~~~

mapper-client.cc and mapper-resolver.cc have addressed this already
by getting <string> and <vector> included; do the same for module.cc.

gcc/cp:
2020-12-22  Gerald Pfeifer  <gerald@pfeifer.com>

	* module.cc (INCLUDE_STRING): Define.
	(INCLUDE_VECTOR): Ditto.