win32: fix implementation of '%z' in strftime

Windows' strftime prints the name of the timezone rather than the
timezone offset for '%z'.  Add a hack to do it properly.

Windows' strftime also uses its own version of the timezone name for
'%Z'.  A workaround for this is to set the TZ environment variable.

1 files changed, 27 insertions, 0 deletions

diff --git a/win32/mingw.c b/win32/mingw.c
index 876b74221..211c378a3 100644
--- a/win32/mingw.c
+++ b/win32/mingw.c
@@ -862,6 +862,33 @@ size_t mingw_strftime(char *buf, size_t max, const char *format, const struct tm
                                 t = newfmt + m + 1;
                                 fmt = newfmt;
                         }
+                        else if ( t[1] == 'z' ) {
+                                char buffer[16] = "";
+
+                                *t = '\0';
+                                m = t - fmt;
+                                _tzset();
+                                if ( tm->tm_isdst >= 0 ) {
+                                        int offset = (int)_timezone - (tm->tm_isdst > 0 ? 3600 : 0);
+                                        int hr, min;
+
+                                        if ( offset > 0 ) {
+                                                buffer[0] = '-';
+                                        }
+                                        else {
+                                                buffer[0] = '+';
+                                                offset = -offset;
+                                        }
+
+                                        hr = offset / 3600;
+                                        min = (offset % 3600) / 60;
+                                        sprintf(buffer+1, "%02d%02d", hr, min);
+                                }
+                                newfmt = xasprintf("%s%s%s", fmt, buffer, t+2);
+                                free(fmt);
+                                t = newfmt + m + 1;
+                                fmt = newfmt;
+                        }
                         else if ( t[1] != '\0' ) {
                                 ++t;
                         }