Bug#869144: systemd: Setting PATH with environment.d does not work

[Stefan Tatschner]

Subject: systemd: Setting PATH with environment.d does not work
Package: systemd
Version: 234-1
Severity: normal

Dear Maintainer,

Setting the $PATH variable with systemd's environment.d feature does not work
as expected. I have this content in my
`~/.config/environment.d/99-defaults.conf`:

```
GOPATH=$HOME/Go
PATH1=$GOPATH/bin:$HOME/.cargo/bin:$HOME/.local/bin:$PATH
PATH=$GOPATH/bin:$HOME/.cargo/bin:$HOME/.local/bin:$PATH
```

After a login in gnome3 I expect to see `$PATH` and `$PATH1` to be equal; with
expanded `$GOPATH` prepended.

On a shell I get this instead:

```
$ printenv PATH PATH1 GOPATH
/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games
/home/stefan/Go/bin:/home/stefan/.cargo/bin:/home/stefan/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
/home/stefan/Go
```

```
$ systemctl --user show-environment
...
GOPATH=/home/stefan/Go
PATH1=/home/stefan/Go/bin:/home/stefan/.cargo/bin:/home/stefan/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/u
PATH=/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games
...
```

`$PATH` seems to be hardcoded somewhere which overwrites my setting; important
fact: I use gnome on **wayland**. So I have no shellscripts that are being
exectued during login.

-- Package-specific info:

-- System Information:
Debian Release: buster/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 4.11.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.utf8, LC_CTYPE=en_US.utf8 (charmap=UTF-8),
LANGUAGE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages systemd depends on:
ii  adduser         3.115
ii  libacl1         2.2.52-3+b1
ii  libapparmor1    2.11.0-6
ii  libaudit1       1:2.7.7-1+b1
ii  libblkid1       2.29.2-2
ii  libc6           2.24-12
ii  libcap2         1:2.25-1
ii  libcryptsetup4  2:1.7.3-4
ii  libgcrypt20     1.7.8-2
ii  libgpg-error0   1.27-3
ii  libidn11        1.33-1
ii  libip4tc0       1.6.1-2
ii  libkmod2        24-1
ii  liblz4-1        0.0~r131-2+b1
ii  liblzma5        5.2.2-1.3
ii  libmount1       2.29.2-2
ii  libpam0g        1.1.8-3.6
ii  libseccomp2     2.3.1-2.1
ii  libselinux1     2.6-3+b2
ii  libsystemd0     234-1
ii  mount           2.29.2-2
ii  procps          2:3.3.12-3
ii  util-linux      2.29.2-2

Versions of packages systemd recommends:
ii  dbus            1.10.20-1
ii  libpam-systemd  234-1

Versions of packages systemd suggests:
ii  policykit-1        0.105-18
pn  systemd-container  <none>

Versions of packages systemd is related to:
pn  dracut           <none>
ii  initramfs-tools  0.130
ii  udev             234-1

-- Configuration Files:
/etc/systemd/resolved.conf changed [not included]

-- no debconf information