[CMake] Coverage support

[Rolf Eike Beer]

Am 2017-08-07 11:06, schrieb Clément Gregoire:
> I usually stop reading Cmakelists.txt as soon as I see this
> 
> set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -pedantic -pthread -g -O0
> -fprofile-arcs -ftest-coverage")

The pthread thing there is likely wrong anyway, and the -Wall is 
entirely optional. The other things are needed, otherwise gcov will not 
produce any useful output.

> Also you need to use the SETUP_TARGET_FOR_COVERAGE for every single 
> test
> target, which seems to be a difficult to scale on big projects

No, you don't. It's entirely fine if you just run "make test" as I do in 
OSM2go.

Eike