The modules declare which configuration variables they need to have
present in config.h, not only their own but also defined in projects
using them.
However, a lot of these variables are not actually used in the headers!
This changeset removes all HAVE_XXX variables which is not present in
any opm/*.h* file in these projects, and thus there is no need for the
client to specify.
Note that only the variables used by the module *itself* should be
listed; the build system will setup the complete list from the
prerequisites.
This define is used by the unit tests; there is no reason why it should
be on the list that must be provided by other projects that use our
headers (the other projects don't use our tests).
This file can be included both in the project itself, and also in the
find module for the library, so that the list of dependencies can be
maintained in only one place.