functions: dynamically query gentoo system paths

Use portageq to retrieve system paths instead of hardcoding them in.
This helps especially in Gentoo Prefix, where the installation is not
in / but rather offset inside a subdirectory (usually a users home
directory).

This only affects the "slow" path. When eix is installed it will be used
instead. It already accounts for Prefix installations.

Closes #12552

share/functions/__fish_print_portage_installed_pkgs.fish

@@ -3,6 +3,6 @@ function __fish_print_portage_installed_pkgs --description 'Print all installed
     if type -f -q eix
         EIX_LIMIT=0 eix -I --only-names
     else
-        find /var/db/pkg -mindepth 2 -maxdepth 2 -type d -printf '%P\n' 2>/dev/null | string replace -r -- '-[0-9][0-9.]*.*$' ''
+        find (portageq envvar vdb_path) -mindepth 2 -maxdepth 2 -type d -printf '%P\n' 2>/dev/null | string replace -r -- '-[0-9][0-9.]*.*$' ''
     end
 end

share/functions/__fish_print_portage_repository_paths.fish

@@ -1,17 +1,6 @@
 # localization: skip(private)
 function __fish_print_portage_repository_paths --description 'Print the paths of all configured repositories'
-    set -l a /etc/portage/repos.conf
-    set -l b
-    set -l c /usr/share/portage/config/repos.conf
-    test -d $a
-    and set b (path filter -f -- $a/**)
-    test -f $a
-    and set b $a
-    test -n "$b"
-    and string match -q "[gentoo]" -- (cat $b 2>/dev/null)
-    and set c $b
-    or set -a c $b
-    path is -r -- $c
-    or return
-    cat $c 2>/dev/null | string match -g -r '^location = (.*$)'
+    set -l eroot (portageq envvar EROOT)
+    set -l repos (portageq get_repos $eroot | string split ' ')
+    portageq get_repo_path $eroot $repos
 end