strbuf: change an always NULL/"" strbuf_addftime() param to bool

strbuf_addftime() allows callers to pass a time zone name for
expanding %Z. The only current caller either passes the empty string
or NULL, in which case %Z is handed over verbatim to strftime(3).
Replace that string parameter with a flag controlling whether to
remove %Z from the format specification. This simplifies the code.

Commit-message-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/strbuf.h b/strbuf.h
index 6708cef..9262615 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -343,11 +343,12 @@ extern void strbuf_vaddf(struct strbuf *sb, const char *fmt, va_list ap);
  * `tz_offset` is in decimal hhmm format, e.g. -600 means six hours west
  * of Greenwich, and it's used to expand %z internally.  However, tokens
  * with modifiers (e.g. %Ez) are passed to `strftime`.
- * `tz_name` is used to expand %Z internally unless it's NULL.
+ * `suppress_tz_name`, when set, expands %Z internally to the empty
+ * string rather than passing it to `strftime`.
  */
 extern void strbuf_addftime(struct strbuf *sb, const char *fmt,
 			    const struct tm *tm, int tz_offset,
-			    const char *tz_name);
+			    int suppress_tz_name);
 
 /**
  * Read a given size of data from a FILE* pointer to the buffer.