Merge branch 'jk/verify-sig-merge-into-void'

"git merge" and "git pull" that merges into an unborn branch used
to completely ignore "--verify-signatures", which has been
corrected.

* jk/verify-sig-merge-into-void:
pull: handle --verify-signatures for unborn branch
merge: handle --verify-signatures for unborn branch
merge: extract verify_merge_signature() helper

diff --cc builtin/merge.c
Simple merge

diff --cc builtin/pull.c
Simple merge

diff --cc commit.c
Simple merge

diff --cc commit.h
index 03ab19508f222a4a9cdfc12e9850eb9e07787230,8e3aeb11142837d9a6a94e639353fd0773a89aaa..98664536cb82c65f04a1742c3e5c1e269afc9493
--- 1/commit.h
--- 2/commit.h
+++ b/commit.h
@@@ -334,12 -357,13 +334,20 @@@ extern int remove_signature(struct strb
   */
  extern int check_commit_signature(const struct commit *commit, struct signature_check *sigc);
  
 +/* record author-date for each commit object */
 +struct author_date_slab;
 +void record_author_date(struct author_date_slab *author_date,
 +                      struct commit *commit);
 +
 +int compare_commits_by_author_date(const void *a_, const void *b_, void *unused);
++
+ /*
+  * Verify a single commit with check_commit_signature() and die() if it is not
+  * a good signature. This isn't really suitable for general use, but is a
+  * helper to implement consistent logic for pull/merge --verify-signatures.
+  */
+ void verify_merge_signature(struct commit *commit, int verbose);
+ 
  int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused);
  int compare_commits_by_gen_then_commit_date(const void *a_, const void *b_, void *unused);