cmake: Add Clang support for coverage generation
cmake: Add Clang support for coverage generation

hioa-cs/IncludeOS,AnnikaH/IncludeOS,mnordsletten/IncludeOS,AnnikaH/IncludeOS,AnnikaH/IncludeOS,alfred-bratterud/IncludeOS,alfred-bratterud/IncludeOS,hioa-cs/IncludeOS,mnordsletten/IncludeOS,alfred-bratterud/IncludeOS,hioa-cs/IncludeOS,alfred-bratterud/IncludeOS,hioa-cs/IncludeOS,AndreasAakesson/IncludeOS,AndreasAakesson/IncludeOS,mnordsletten/IncludeOS,mnordsletten/IncludeOS,AnnikaH/IncludeOS,alfred-bratterud/IncludeOS,hioa-cs/IncludeOS,AndreasAakesson/IncludeOS,mnordsletten/IncludeOS,AnnikaH/IncludeOS,AndreasAakesson/IncludeOS,mnordsletten/IncludeOS,AndreasAakesson/IncludeOS,AndreasAakesson/IncludeOS