https://chromium.googlesource.com/chromiumos/third_party/shellcheck/

Uses the `portageq` command to scan for repositories, which in turn are
scanned for eclasses, which are then scanned for eclass variables.

The variables are scanned using a heuristic which looks for

    "# @ECLASS_VARIABLE: "

at the start of each line, which means only properly documented
variables will be found.

Signed-off-by: hololeap <hololeap@users.noreply.github.com>

Creates a Map of eclass names to eclass variables by scanning the
system for repositories and their respective eclasses. Runs `portageq`
to determine repository names and locations. Emits a warning if an
IOException is caught when attempting to run `portageq`.

This Map is passed via CheckSpec to AnalysisSpec and finally to
Parameters, where it is read by `checkUnusedAssignments` in order to
determine which variables can be safely ignored by this check.

Signed-off-by: hololeap <hololeap@users.noreply.github.com>

The Gentoo eclass list is now populated using pure Haskell. The old
python generators and generated module are no longer needed.

Signed-off-by: hololeap <hololeap@users.noreply.github.com>

Signed-off-by: hololeap <hololeap@users.noreply.github.com>