There is a new pull request by jjsullivan5196 against master on the void-packages repository

https://github.com/jjsullivan5196/void-packages lcov-1.15
https://github.com/void-linux/void-packages/pull/24315

lcov: update to 1.15.
As of the GCC 9 series, lcov 1.14 and earlier are no longer compatible with GCC coverage data. 1.15 fixes compatibility with newer GCC releases (lcov will not attempt to build reports). I tested this with a medium-sized C++ project and got full coverage results in the report. More info https://github.com/linux-test-project/lcov/issues/58

A patch file from https://github.com/void-linux/void-packages/pull/24315.patch is attached