Modern gcovr includes html generation support so if lcov and
genhtml are not available fallback to gcovr.
Kept lcov and genhtml as default so to not surprise existing
users of coverage-html with the different output of gcovr.
gcovr added html support in 3.0 but as there already is a test
for 3.1 because of the changes to -r/--rootdir I opted to only
allow html generation for >= 3.1 to keep things simple.
In gcovr 3.1 the -r/--rootdir argument changed meaning causing
reports generated with gcovr 3.1 to not find the source files
and look for *.gcda in the whole source tree rather than the
build dir.
So, detect gcovr version and if 3.1 give build_root to -r instead
of source_root.
Cuurently, a set of directories is filtered out from the output based on
the location of system includes on most common linux distro's. This
commit does away with the blacklist and implements a whitelist approach:
only the files inside the source root are shown.
Joel Klinghed
Henk van der Laan
Félix Piédallu
snsmac
Stefan Sonski
Jussi Pakkanen