Merge branch 'jc/cutoff-config'

"[gc] rerereResolved = 5.days" used to be invalid, as the variable
is defined to take an integer counting the number of days.  It now
is allowed.

* jc/cutoff-config:
  rerere: allow approxidate in gc.rerereResolved/gc.rerereUnresolved
  rerere: represent time duration in timestamp_t internally
  t4200: parameterize "rerere gc" custom expiry test
  t4200: gather "rerere gc" together
  t4200: make "rerere gc" test more robust
  t4200: give us a clean slate after "rerere gc" tests

config.h

@@ -215,6 +215,9 @@ extern int git_config_get_max_percent_split_change(void);
 /* This dies if the configured or default date is in the future */
 extern int git_config_get_expiry(const char *key, const char **output);
 
+/* parse either "this many days" integer, or "5.days.ago" approxidate */
+extern int git_config_get_expiry_in_days(const char *key, timestamp_t *, timestamp_t now);
+
 struct key_value_info {
 	const char *filename;
 	int linenr;