Description:

In a modern system the scripts in `/etc/profile.d/` are run multiple times.
For example, once by the login manager sddm, and again by the virtual terminal konsole.

If `/etc/profile.d/*.sh` scripts use something like `export PATH=$PATH:/usr/lib/rustup/bin` to append to $PATH,
this causes duplicate entries to appear in PATH.

This is why `/etc/profile` has the function `append_path`. The above example should be `append_path "/usr/lib/rustup/bin"`.

Additional info:
* package version(s)
plan9port 20230331-1
rustup 1.26.0-3

plan9port and rustup are the only affected packages I found in my system. If you have access to every package in Arch Linux, the following script should help find affected packages.
```
for file in *.pkg.tar.zst; do bsdtar xvfO "$file" etc/profile.d/ | tr '\0' '\n'; done 2>&1 | grep -v -E '^bsdtar:' | grep -E '^x|\$\{?PATH'
```