\param name the name of the variable to set.
\param value the value of the variable to set.
\param overwrite 1 to overwrite the variable if it exists, 0 to return
success without setting the variable if it already exists.
\returns 0 on success, -1 on error.
\threadsafety This function is not thread safe, consider using
SDL_SetEnvironmentVariable() instead.
\since This function is available since SDL 3.2.0.
Set the value of a variable in the environment.
\param name the name of the variable to set. \param value the value of the variable to set. \param overwrite 1 to overwrite the variable if it exists, 0 to return success without setting the variable if it already exists. \returns 0 on success, -1 on error.
\threadsafety This function is not thread safe, consider using SDL_SetEnvironmentVariable() instead.
\since This function is available since SDL 3.2.0.
\sa SDL_SetEnvironmentVariable