Fix GH-10766: PharData archive created with Phar::Zip format does not keep files metadata (datetime)

Due to an incorrect check, the datetime was never actually set.
To test this we need to write the file using phar, but read the file
using a different method to not get a cached, or a value that's been
transformed twice and is therefore accidentally correct.

Closes GH-10769

NEWS

@@ -12,6 +12,10 @@ PHP                                                                        NEWS
 - Opcache:
   . Fixed build for macOS to cater with pkg-config settings. (David Carlier)
 
+- Phar:
+  . Fixed bug GH-10766 (PharData archive created with Phar::Zip format does
+    not keep files metadata (datetime)). (nielsdos)
+
 16 Mar 2023, PHP 8.1.17
 
 - Core:

ext/phar/tests/zip/gh10766.phpt

@@ -0,0 +1,26 @@
+--TEST--
+GH-10766 (PharData archive created with Phar::Zip format does not keep files metadata (datetime))
+--EXTENSIONS--
+phar
+zip
+--INI--
+phar.readonly=0
+--FILE--
+<?php
+$phar = new PharData(__DIR__ . '/gh10766.zip', 0, null, Phar::ZIP);
+$phar->addFromString('name', 'contents');
+unset($phar);
+
+// Re-read from disk, but using the zip extension because the phar bug will not make it possible
+// to use their timestamp methods.
+$zip = new ZipArchive();
+$zip->open(__DIR__ . '/gh10766.zip');
+var_dump($zip->statName('name')['mtime'] > 315529200 /* earliest possible zip timestamp */);
+$zip->close();
+?>
+--CLEAN--
+<?php
+unlink(__DIR__ . '/gh10766.zip');
+?>
+--EXPECT--
+bool(true)

ext/phar/zip.c

@@ -147,7 +147,8 @@ static void phar_zip_u2d_time(time_t time, char *dtime, char *ddate) /* {{{ */
 	struct tm *tm, tmbuf;
 
 	tm = php_localtime_r(&time, &tmbuf);
-	if (tm->tm_year >= 1980) {
+	/* Note: tm_year is the year - 1900 */
+	if (tm->tm_year >= 80) {
 		cdate = ((tm->tm_year+1900-1980)<<9) + ((tm->tm_mon+1)<<5) + tm->tm_mday;
 		ctime = ((tm->tm_hour)<<11) + ((tm->tm_min)<<5) + ((tm->tm_sec)>>1);
 	} else {