[PATCH v2 0/6] Add some string_list-related functions

Version 2 of a patch series that adds some functions to the string_list API. This patch series applies to current master. Thanks for Junio for lots of great feedback.

The patch series "Clean up how fetch_pack() handles the heads list" v3, which requires some of the new string_list functionality, works unmodified on top of this version of the patch series.

Changes since v1:

* Expose a new function, string_list_append_nodup().  This is used in
  the implementation of string_list_split() and should be generally
  useful.

* Straighten out the API for splitting strings (with help from Junio):

  * Implement two separate functions, one for splitting strings in
    place and a second for making copies while splitting a const
    string.

  * Redefine maxsplit=0 to mean "copy input string to output list as a
    single entry" for better consistency.

* Add tests for more of the new functionality and simplify some of the
  other tests.

* Various comment and documentation improvements.

Michael Haggerty (6):
  string_list: add function string_list_append_nodup()
  string_list: add two new functions for splitting strings
  string_list: add a new function, filter_string_list()
  string_list: add a new function, string_list_remove_duplicates()
  string_list: add a function string_list_longest_prefix()
  api-string-list.txt: initialize the string_list the easy way

 .gitignore                                  |   1 +
 Documentation/technical/api-string-list.txt |  67 +++++++++++++--
 Makefile                                    |   1 +
 string-list.c                               | 123 ++++++++++++++++++++++++++--
 string-list.h                               |  71 ++++++++++++++++
 t/t0063-string-list.sh                      | 121 +++++++++++++++++++++++++++
 test-string-list.c                          | 123 ++++++++++++++++++++++++++++
 7 files changed, 497 insertions(+), 10 deletions(-)
 create mode 100755 t/t0063-string-list.sh
 create mode 100644 test-string-list.c