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We sometimes write static initialization code like

const bool c_useCudaLaunchKernel = (GMX_CUDA_VERSION >= 7000) && (getenv("GMX_DISABLE_CUDALAUNCH") == nullptr);

so that we can have configure-time defaults with run-time overrides. However there's a risk that something else being constructed at init time might depend on the order of such initialization and strange non-reproducible behaviour result.

/* Implements the "construct on first use" idiom to avoid any static
 * initialization order fiasco.
 *
 * Note that thread-safety of the initialization is guaranteed by the
 * C++11 language standard.
 *
 * The pointer itself (not the memory it points to) has no destructor,
 * so there is no deinitialization issue.  See
 * https://isocpp.org/wiki/faq/ctors for discussion of alternatives
 * and trade-offs. */
const PmeTestEnvironment *getPmeTestEnv()
{
    static PmeTestEnvironment *pmeTestEnvironment = nullptr;
    if (pmeTestEnvironment == nullptr)
    {
        // Ownership of the TestEnvironment is taken by GoogleTest, so nothing can leak
        pmeTestEnvironment = static_cast<PmeTestEnvironment *>(::testing::AddGlobalTestEnvironment(new PmeTestEnvironment));
    }
    return pmeTestEnvironment;
}

We should probably rework any such use of getenv(), and maybe have the checker prevent us adding new ones.