nextcloud php extension sysvsem

[loki279]

Hello,
since version 26 of nextcloud the php extension sysvsem should be enabled, otherwise there is a caution message in the admins page:
$this->bbcode_second_pass_code('', '
This instance is missing some recommended PHP modules. For improved performance and better compatibility it is highly recommended to install them.

sysvsem
')

So my question is, how do I enable this extension. I set
$this->bbcode_second_pass_code('', '
extension=sysvsem
')

in php.ini

the arch wiki tells me also to enable the extension for php-fpm but I'm unsure how to do that.

$this->bbcode_second_pass_code('', '
php_value[extension] = sysvsem
')

did not do the trick. Also there are no packages for sysvsem that I could install in the repository. My x86_64 has several packages in the aur for different php versions...