OLD_ENV_VALUE
old_env_var = OLD_ENV_VALUE;
old_env_value = OLD_ENV_VALUE;
old_env_var = OLD_ENV_VALUE;
int old_env_value = OLD_ENV_VALUE;
#define old_env_value OLD_ENV_VALUE
old_env_value = OLD_ENV_VALUE;
case OLD_ENV_VALUE:
if (old_env_var == OLD_ENV_VALUE)