Arch Linux

Description:
The package for Perl 5.30.0-2 seems to introduce a regression when setting $EFFECTIVE_GROUP_ID with more than one group id. This breaks (at least) all non-as-root plugins in munin-node, which fails with the following error.

```
2019/06/16-21:47:33 [9483] Configuring cpu
2019/06/16-21:47:33 [9483] Error output from cpu:
2019/06/16-21:47:33 [9483] 2019/06/16-21:47:33 [9590] # FATAL: Plugin 'cpu' Can't drop privileges: at /usr/share/perl5/vendor_perl/Munin/Node/Service.pm line 228.\n.
2019/06/16-21:47:33 [9483] Service 'cpu' exited with status 1/0.
```

This worked with Perl 5.28.2-1, and downgrading back to it fixes the issue.


Additional info:
* package version(s) 5.30.0-2
* Perl 5.3.0 modules:
```
$ pacman -Qo '/usr/lib/perl5/5.30'
/usr/lib/perl5/5.30/ is owned by cairo-perl 1.106-8
/usr/lib/perl5/5.30/ is owned by glib-perl 1.329-2
/usr/lib/perl5/5.30/ is owned by gtk2-perl 1.24992-4
/usr/lib/perl5/5.30/ is owned by hamlib 3.3-3
/usr/lib/perl5/5.30/ is owned by imagemagick 7.0.8.49-1
/usr/lib/perl5/5.30/ is owned by irssi 1.2.0-4
/usr/lib/perl5/5.30/ is owned by libproxy 0.4.15-10
/usr/lib/perl5/5.30/ is owned by net-snmp 5.8-4
/usr/lib/perl5/5.30/ is owned by pango-perl 1.227-11
/usr/lib/perl5/5.30/ is owned by perl-alien-build 1.74-3
/usr/lib/perl5/5.30/ is owned by perl-alien-libxml2 0.09-2
/usr/lib/perl5/5.30/ is owned by perl-anyevent 4:7.15-2
/usr/lib/perl5/5.30/ is owned by perl-authen-sasl 2.16-6
/usr/lib/perl5/5.30/ is owned by perl-capture-tiny 0.48-2
/usr/lib/perl5/5.30/ is owned by perl-clone 0.41-3
/usr/lib/perl5/5.30/ is owned by perl-convert-asn1 0.27-5
/usr/lib/perl5/5.30/ is owned by perl-dbi 1.642-3
/usr/lib/perl5/5.30/ is owned by perl-error 0.17027-2
/usr/lib/perl5/5.30/ is owned by perl-ffi-checklib 0.24-2
/usr/lib/perl5/5.30/ is owned by perl-file-which 1.23-2
/usr/lib/perl5/5.30/ is owned by perl-io-socket-inet6 2.72-5
/usr/lib/perl5/5.30/ is owned by perl-ldap 0.65-6
/usr/lib/perl5/5.30/ is owned by perl-libintl-perl 1.31-3
/usr/lib/perl5/5.30/ is owned by perl-mailtools 2.21-2
/usr/lib/perl5/5.30/ is owned by perl-net-ldap-server 0.43-7
/usr/lib/perl5/5.30/ is owned by perl-net-server 2.009-4
/usr/lib/perl5/5.30/ is owned by perl-path-tiny 0.108-2
/usr/lib/perl5/5.30/ is owned by perl-socket6 0.29-3
/usr/lib/perl5/5.30/ is owned by perl-text-iconv 1.7-17
/usr/lib/perl5/5.30/ is owned by perl-text-soundex 3.05-7
/usr/lib/perl5/5.30/ is owned by perl-timedate 2.30-6
/usr/lib/perl5/5.30/ is owned by perl-uri 1.76-2
/usr/lib/perl5/5.30/ is owned by perl-xml-libxml 2.0201-2
/usr/lib/perl5/5.30/ is owned by perl-xml-parser 2.44-9
/usr/lib/perl5/5.30/ is owned by perl-yaml 1.29-2
```

Steps to reproduce:
$ sudo perl -e 'print "old: $)"; print "->"; $)="1000 985"; print "new: $)\n"; print "error $!\n" if $!;'
** With perl-5.30.0-2
```
old: 0 0->new: 1000 0
error Invalid argument
```
** With perl-5.28.2-1
```
old: 0 0->new: 1000 985
```