Fix GH-8923: error_log on Windows can hold the file write lock

On Windows, closing a file which is locked may not immediately remove
the lock.  The `LockFileEx()` documentation states:

| Therefore, it is recommended that your process explicitly unlock all
| files it has locked when it terminates.

We comply, and also use the macro `LOCK_EX` instead of the magic number
`2`.

Closes GH-8925.

Author: cmb69

NEWS

@@ -2,6 +2,9 @@ PHP                                                                        NEWS
 |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 ?? ??? 2022, PHP 8.0.22
 
+- Core:
+  . Fixed bug GH-8923 (error_log on Windows can hold the file write lock). (cmb)
+
 - Date:
   . Fixed bug #80047 (DatePeriod doesn't warn with custom DateTimeImmutable).
     (Derick)

main/main.c

@@ -837,9 +837,10 @@ PHPAPI ZEND_COLD void php_log_err_with_severity(const char *log_message, int sys
 #endif
 			len = spprintf(&tmp, 0, "[%s] %s%s", ZSTR_VAL(error_time_str), log_message, PHP_EOL);
 #ifdef PHP_WIN32
-			php_flock(fd, 2);
+			php_flock(fd, LOCK_EX);
 			/* XXX should eventually write in a loop if len > UINT_MAX */
 			php_ignore_value(write(fd, tmp, (unsigned)len));
+			php_flock(fd, LOCK_UN);
 #else
 			php_ignore_value(write(fd, tmp, len));
 #endif