Sure but I ran an out-of-the-box CLion with out-of-the-box CMake, compiled a popular open source project that in theory is cross platform compatible with Mac, a

Sure but I ran an out-of-the-box CLion with out-of-the-box CMake, compiled a popular open source project that in theory is cross platform compatible with Mac, and it fails in a C standard library header deep inside Apple's headers after a chain of "#include_next" because it didn't find "/usr/include". Is this a fault of mine, Jetbrains, Kitware, or Apple?