lcov: filter depends from coverage report
Summary:
If you build the binaries with the depends folder and then generate coverage reports with make cov, depends will be included in the coverage reports. Coverage of the dependencies are not that interesting and should be filtered.
Backport of core PR17647.
Depends on D5301.
Test Plan:
../configure --prefix=$PWD/../depends/x86_64-linux-gnu --enable-lcov make make cov
Check there is no depends/ subdir under total.coverage.
Reviewers: #bitcoin_abc, jasonbcox
Reviewed By: #bitcoin_abc, jasonbcox
Differential Revision: https://reviews.bitcoinabc.org/D5303