Motivation for this change

Update lcov from 1.14 to 1.15. This removes some applied patches and adds support for gcc 9.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
  • Created project with
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.\

Tested by making a small project and generating coverage:

// main.cpp
#include <iostream>

int main(int argc, char* argv[]) {
  if (argc == 1)
    std::cout << "hello, world!\n";
  else
    std::cout << "goodbye, world\n";

  return 0;
}

# lcov.sh
#!/usr/bin/env bash

lcov --no-external --capture --initial --directory . --output-file /tmp/test_base.info
./build/test abc
lcov --no-external --capture --directory . --output-file /tmp/test_test.info

lcov --add-tracefile /tmp/test_base.info --add-tracefile /tmp/test_test.info --output-file /tmp/test_total.info
rm -rf /tmp/test-lcov/
mkdir /tmp/test-lcov/

genhtml --prefix . --ignore-errors source /tmp/test_total.info --legend --title "commit SHA1" --output-directory=/tmp/test-lcov

# CMakeLists.txt
cmake_minimum_required(VERSION 3.17)
project(TestProject)

add_executable(test main.cpp)
target_compile_options(test PRIVATE -fprofile-arcs -ftest-coverage)
target_link_libraries(test -fprofile-arcs)