Function svn_config_merge 

pub unsafe extern "C" fn svn_config_merge(
    cfg: *mut svn_config_t,
    file: *const c_char,
    must_exist: svn_boolean_t,
) -> *mut svn_error_t

Like svn_config_read(), but merges the configuration data from @a file (a file or registry path) into @a *cfg, which was previously returned from svn_config_read(). This function invalidates all value expansions in @a cfg, so that the next svn_config_get() takes the modifications into account.