How to create two identical PHP phar-archives - php

Question

I'm currently trying to distribute software written in PHP via executible phar-archive. The main problem is that output archive always have different md5 sum in subsequent creation, even if source files are not modified.
This cause several issues while deploying application with ansible: phar-file is always "new" so it is impossible to mitigate some post-deploy actions in playbook even if file contents is actually unchanged.
Here is sample script I use to create archive.
<?php
$phar_file = 'out.phar';
$src = [ '1.php', '2.php' ];
$stub = <<<EOF
#!/usr/bin/php
<?php
Phar::mapPhar('{$phar_file}');
include 'phar://{$phar_file}/1.php';
__HALT_COMPILER();
EOF;
#unlink($phar_file);
$p = new Phar($phar_file);
$p->startBuffering();
foreach ($src as $f) {
$p->addFile($f);
}
$p->setStub($stub);
$p->stopBuffering();
Let's try it:
# php7 create-phar.php
# md5sum out.phar
5e0cdadb7953af4f1a67a2a0852e3a85 out.phar
# php7 create-phar.php
# md5sum out.phar
4c97e3f67cf6f168c317235bc18299ea out.phar
Cmp tells, that there are two two bytes changed in header, also signature differs:
# cmp -l out.phar out.phar.old
140 157 120
173 157 120
3721 163 236
3722 5 235
3723 247 137
3724 246 160
3725 267 145
3726 52 174
3727 366 230
3728 22 322
3729 34 357
3730 45 176
3731 53 62
3732 130 142
3733 276 110
3734 20 252
3735 176 151
3736 134 105
3737 236 3
3738 62 16
3739 334 142
3740 176 244
Is it possible to create binary equal phar-archive from the same sources and how?
Thank you!