strptime loses one hour if TZ set to Dublin

[Mark Burkley]

glibc version 2.28-0ubuntu1

If timezone is set to Dublin, strptime returns one hour less than it should. Timezone set to London works fine, but Dublin and London are in the same time zone. DST is not active.

mark@sotera:~/build-glibc$ TZ='Europe/Dublin'; ./test
t(orig)=1551972563
s=2019-03-07T15:29:23GMT+0000

calling strptime
t(new)=1551968963
s=2019-03-07T14:29:23

mark@sotera:~/build-glibc$ TZ='Europe/London'; ./test
t(orig)=1551972570
s=2019-03-07T15:29:30GMT+0000
calling strptime
t(new)=1551972570
s=2019-03-07T15:29:30

where test.c is the following:

#define _XOPEN_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <time.h>

int main (void)
{
    struct tm tms;
    time_t t;
    char s[100];
    int sec;

    t = time (NULL);
    printf ("t(orig)=%d\n", (int) t);

    gmtime_r (&t, &tms);
    strftime (s, 90, "%Y-%m-%dT%H:%M:%S%Z%z", &tms);
    printf ("s=%s\n", s);

    memset (&tms, 0, sizeof (struct tm));
    printf("calling strptime\n");
    char *unproc = strptime (s, "%Y-%m-%dT%H:%M:%S%Z", &tms);
    t = mktime(&tms);
    printf ("t(new)=%d\n", (int) t);

    gmtime_r (&t, &tms);
    strftime (s, 90, "%Y-%m-%dT%H:%M:%S", &tms);
    printf ("s=%s\n", s);

    return 0;
}