Fix %Z parsing in strptime [BZ #16088]

[Stanley Lancaster <lancasterharp@gmail.com>]

---
 time/strptime_l.c   | 5 ++++-
 time/tst-strptime.c | 1 +
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/time/strptime_l.c b/time/strptime_l.c
index 85c3249fcc..5954015c4e 100644
--- a/time/strptime_l.c
+++ b/time/strptime_l.c
@@ -770,9 +770,12 @@ __strptime_internal (const char *rp, const char *fmt, struct tm *tmp,
 	  break;
 	case 'Z':
 	  /* Read timezone but perform no conversion.  */
+	  /* we recognize the format [-+a-zA-Z0-9]{3,} */
 	  while (ISSPACE (*rp))
 	    rp++;
-	  while (!ISSPACE (*rp) && *rp != '\0')
+	  
+	  const char* stop_rp = rp + 3;
+	  while (((*rp >= 'A' && *rp <= 'Z') || (*rp >= 'a' && *rp <= 'z') || (*rp >= '0' && *rp <= '9')) && (rp < stop_rp) && *rp != '\0')
 	    rp++;
 	  break;
 	case 'z':
diff --git a/time/tst-strptime.c b/time/tst-strptime.c
index 3dae9e0594..31d6945ef1 100644
--- a/time/tst-strptime.c
+++ b/time/tst-strptime.c
@@ -38,6 +38,7 @@ static const struct
   { "C", "03/03/00", "%D", 5, 62, 2, 3 },
   { "C", "9/9/99", "%x", 4, 251, 8, 9 },
   { "C", "19990502123412", "%Y%m%d%H%M%S", 0, 121, 4, 2 },
+  { "C", "1999CST0502123412", "%Y%Z%m%d%H%M%S", 0, 121, 4, 2 },
   { "C", "2001 20 Mon", "%Y %U %a", 1, 140, 4, 21 },
   { "C", "2001 21 Mon", "%Y %W %a", 1, 140, 4, 21 },
   { "C", "2001 21 Mon", "%2000Y %W %a", 1, 140, 4, 21 },
-- 
2.39.3