Merge branch 'js/difftool-no-index'

"git difftool" can now run outside a repository.

* js/difftool-no-index:
difftool: allow running outside Git worktrees with --no-index
parse-options: make OPT_ARGUMENT() more useful
difftool: remove obsolete (and misleading) comment

diff --cc git.c
Simple merge

diff --cc parse-options.c
Simple merge

diff --cc parse-options.h
index 0f7378706610bc9cf394d012e5cd02ef272b5ef4,c3d45ba1ac1cefb6c2a7877d02e753a0c4c3ea4b..cc9230adacb61f2a5066ac094c66bdfd18534354
--- 1/parse-options.h
--- 2/parse-options.h
+++ b/parse-options.h
@@@ -136,12 -136,10 +136,12 @@@ struct option 
  #define OPT_BOOL_F(s, l, v, h, f)   OPT_SET_INT_F(s, l, v, h, 1, f)
  #define OPT_CALLBACK_F(s, l, v, a, h, f, cb)                  \
        { OPTION_CALLBACK, (s), (l), (v), (a), (h), (f), (cb) }
 +#define OPT_STRING_F(s, l, v, a, h, f)   { OPTION_STRING,  (s), (l), (v), (a), (h), (f) }
 +#define OPT_INTEGER_F(s, l, v, h, f)     { OPTION_INTEGER, (s), (l), (v), N_("n"), (h), (f) }
  
  #define OPT_END()                   { OPTION_END }
- #define OPT_ARGUMENT(l, h)          { OPTION_ARGUMENT, 0, (l), NULL, NULL, \
-                                     (h), PARSE_OPT_NOARG}
+ #define OPT_ARGUMENT(l, v, h)       { OPTION_ARGUMENT, 0, (l), (v), NULL, \
+                                     (h), PARSE_OPT_NOARG, NULL, 1 }
  #define OPT_GROUP(h)                { OPTION_GROUP, 0, NULL, NULL, NULL, (h) }
  #define OPT_BIT(s, l, v, h, b)      OPT_BIT_F(s, l, v, h, b, 0)
  #define OPT_BITOP(s, l, v, h, set, clear) { OPTION_BITOP, (s), (l), (v), NULL, (h), \