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.c

@@ -2094,6 +2094,28 @@ int git_config_get_expiry(const char *key, const char **output)
 	return ret;
 }
 
+int git_config_get_expiry_in_days(const char *key, timestamp_t *expiry, timestamp_t now)
+{
+	char *expiry_string;
+	intmax_t days;
+	timestamp_t when;
+
+	if (git_config_get_string(key, &expiry_string))
+		return 1; /* no such thing */
+
+	if (git_parse_signed(expiry_string, &days, maximum_signed_value_of_type(int))) {
+		const int scale = 86400;
+		*expiry = now - days * scale;
+		return 0;
+	}
+
+	if (!parse_expiry_date(expiry_string, &when)) {
+		*expiry = when;
+		return 0;
+	}
+	return -1; /* thing exists but cannot be parsed */
+}
+
 int git_config_get_untracked_cache(void)
 {
 	int val = -1;