[PATCH 0/2] die_for_incompatible_opts(): unbounded number of options

We have die_for_incompatible_optN() (for 2 <= N <= 4) to check and complain when two or more among N mutually incompatible options are used.

What should a developer do if there are more than four options that cannot be used at once?

Introduce die_for_incompatible_opts(), which can handle an arbitrary number of mutually exclusive options. This is done in two steps:

 - The API for existing functions takes N pairs (for 2 <= N <= 4) of
   'int set, const char *name' parameters that signal which options
   are set.  This parameter order is inconvenient for varargs, where
   a sentinel value marks the end of the argument list (and there is
   no clear sentinel value of type 'int').  The first patch rewrites
   all implementations and callers of die_for_incompatible_optN() to
   swap the parameter order to pairs of 'const char *name, int set'.

 - The second patch then introduces die_for_incompatible_opts(),
   which takes an arbitrary number of 'const char *name, int set'
   pairs terminated by a NULL sentinel.

We could do without the first step and use the 'const char *, int' order only in die_for_incompatible_opts(), leaving the traditional die_for_incompatible_opt[234]() functions using the 'int, const char *' order, but using a consistent ordering is likely easier in the long run.

 1/2: die_for_incompatible_optN: swap the order of arguments
 2/2: die_for_incompatible_opts(): accept more than four options

 builtin/add.c          |  6 +++---
 builtin/clone.c        |  8 ++++----
 builtin/commit.c       | 24 ++++++++++++------------
 builtin/difftool.c     |  6 +++---
 builtin/gc.c           |  8 ++++----
 builtin/grep.c         |  6 +++---
 builtin/log.c          |  6 +++---
 builtin/merge-tree.c   |  8 ++++----
 builtin/pack-objects.c | 21 ++++++++++-----------
 builtin/push.c         |  8 ++++----
 builtin/repack.c       | 12 +++++++-----
 builtin/replay.c       | 18 +++++++++---------
 builtin/rev-list.c     |  6 +++---
 builtin/show-ref.c     |  7 ++++---
 parse-options.c        | 26 ++++++++++++++------------
 parse-options.h        | 40 +++++++++++++++++++++++-----------------
 revision.c             | 26 +++++++++++++-------------
 17 files changed, 123 insertions(+), 113 deletions(-)