nmc_strsplit_set() handles max_token wrong. It cannot call
g_strsplit_set() with max_token first, and then split empty
words. You cannot use g_strsplit_set() to achieve what
nmc_strsplit_set() wants to do, unless you first split all
tokens, then them construct them together again -- thereby
loosing the delimiters.
Anyway, there are just a few caller that do essentially the same.
Refactor the code to not use nmc_strsplit_set().