git: 0948c4d4a330 - releng/15.0 - libc: Add "Z" as TZ designator for strptime.

The branch releng/15.0 has been updated by cperciva:

URL: https://cgit.FreeBSD.org/src/commit/?id=0948c4d4a3308737879342d87efc311913ee4335

commit 0948c4d4a3308737879342d87efc311913ee4335
Author:     Gordon Tetlow <gordon@FreeBSD.org>
AuthorDate: 2025-10-15 22:24:06 +0000
Commit:     Colin Percival <cperciva@FreeBSD.org>
CommitDate: 2025-10-22 20:12:30 +0000

    libc: Add "Z" as TZ designator for strptime.
    
    ISO 8601 allows use of "Z" as the time zone designator. Update the
    strptime parser to allow this usage.
    
    While we are at it, update the manpage to reflect that both UTC and Z
    are now valid options.
    
    Approved by:    re (cperciva)
    Reviewed by:    des
    MFC after:      1 week
    Differential Revision:  https://reviews.freebsd.org/D53083
    
    (cherry picked from commit 79e57ea662d92ffcbe7d65854a284aefac6a332d)
    (cherry picked from commit 3d368c699b73cc1dff3ca27d29d19666741d9ff8)
---
 lib/libc/stdtime/strptime.3 | 2 +-
 lib/libc/stdtime/strptime.c | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/libc/stdtime/strptime.3 b/lib/libc/stdtime/strptime.3
index 7df73d2d080a..9456fa757b85 100644
--- a/lib/libc/stdtime/strptime.3
+++ b/lib/libc/stdtime/strptime.3
@@ -171,7 +171,7 @@ is taken as noon.
 The
 .Fa %Z
 format specifier only accepts time zone abbreviations of the local time zone,
-or the value "GMT".
+and the values "GMT", "UTC", or "Z".
 This limitation is because of ambiguity due to of the over loading of time
 zone abbreviations.
 One such example is
diff --git a/lib/libc/stdtime/strptime.c b/lib/libc/stdtime/strptime.c
index 5f1293c7a267..375e49146639 100644
--- a/lib/libc/stdtime/strptime.c
+++ b/lib/libc/stdtime/strptime.c
@@ -546,7 +546,8 @@ label:
 				zonestr[cp - buf] = '\0';
 				tzset();
 				if (0 == strcmp(zonestr, "GMT") ||
-				    0 == strcmp(zonestr, "UTC")) {
+				    0 == strcmp(zonestr, "UTC") ||
+				    0 == strcmp(zonestr, "Z")) {
 				    *GMTp = 1;
 				} else if (0 == strcmp(zonestr, tzname[0])) {
 				    tm->tm_isdst = 0;