[gtk: 1/2] calendar: Use the new "%OB" format in strftime()

[Matthias Clasen <matthiasc src gnome org>]

commit b9ea25c25c031d2aca64662eaaa7251ac84c78e1
Author: Rafal Luzynski <digitalfreak lingonborough com>
Date:   Sat Feb 10 14:07:56 2018 +0100

    calendar: Use the new "%OB" format in strftime()
    
    Due to the recent changes introduced in glibc 2.27 "%OB" is the
    correct format to obtain a month name as used in the calendar
    header.  The same rule has been working in BSD family (including
    OS X) since 1990s.  This change is simple but makes GTK+ 4.x require
    glibc >= 2.27.  If this requirement cannot be fulfilled then we must
    cherry-pick the full commit cbf118c from gtk-3-22 branch.
    
    Closes: #9

 gtk/gtkcalendar.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtkcalendar.c b/gtk/gtkcalendar.c
index 5bbb6cac19..a93d92e384 100644
--- a/gtk/gtkcalendar.c
+++ b/gtk/gtkcalendar.c
@@ -687,7 +687,7 @@ gtk_calendar_init (GtkCalendar *calendar)
       {
 #ifndef G_OS_WIN32
         tmp_time= (i+3)*86400;
-        strftime ( buffer, sizeof (buffer), "%a", gmtime (&tmp_time));
+        strftime (buffer, sizeof (buffer), "%a", gmtime (&tmp_time));
         default_abbreviated_dayname[i] = g_locale_to_utf8 (buffer, -1, NULL, NULL, NULL);
 #else
         if (!GetLocaleInfoW (GetThreadLocale (), LOCALE_SABBREVDAYNAME1 + (i+6)%7,
@@ -703,7 +703,8 @@ gtk_calendar_init (GtkCalendar *calendar)
       {
 #ifndef G_OS_WIN32
         tmp_time=i*2764800;
-        strftime ( buffer, sizeof (buffer), "%B", gmtime (&tmp_time));
+        /* Note: "%OB" works only in glibc >= 2.27 and in BSD and OS X.  */
+        strftime (buffer, sizeof (buffer), "%OB", gmtime (&tmp_time));
         default_monthname[i] = g_locale_to_utf8 (buffer, -1, NULL, NULL, NULL);
 #else
         if (!GetLocaleInfoW (GetThreadLocale (), LOCALE_SMONTHNAME1 + i,