* jk/maint-config-param:
  config: use strbuf_split_str instead of a temporary strbuf
  strbuf: allow strbuf_split to work on non-strbufs
  config: avoid segfault when parsing command-line config
  config: die on error in command-line config
  fix "git -c" parsing of values with equals signs
  strbuf_split: add a max parameter