ccache toolconf module should use CMAKE_CXX_COMPILER_LAUNCHER and CMAKE_C_COMPILER_LAUNCHER properties instead of RULE_LAUNCH_COMPILE. RULE_LAUNCH_COMPILE is intended for ctest usage(https://cmake.org/cmake/help/latest/prop_gbl/RULE_LAUNCH_COMPILE.html). https://github.com/mustafakemalgilor/hadouken/blob/7d0447fcadf8e93d25f242b9bb251ecbcf67f8cb/cmake/modules/toolconf/CCache.cmake#L29