Build fails for aix/ppc64 target

[jtroy]

Overview of the Issue

packer-plugin-sdk fails to build for the aix/ppc64 compiler target.

Reproduction Steps

$ GOOS=aix GOARCH=ppc64 go build ./...
# github.com/hashicorp/packer-plugin-sdk/pathing
pathing/config_file.go:41:9: undefined: configDir
pathing/config_file.go:88:28: undefined: defaultConfigFile
# github.com/bgentry/speakeasy
../../../go/pkg/mod/github.com/bgentry/speakeasy@v0.1.0/speakeasy.go:23:18: undefined: getPassword
# github.com/hashicorp/go-sockaddr
../../../go/pkg/mod/github.com/hashicorp/go-sockaddr@v1.0.2/route_info.go:14:10: undefined: routeInfo
../../../go/pkg/mod/github.com/hashicorp/go-sockaddr@v1.0.2/ifaddrs.go:116:13: undefined: NewRouteInfo
../../../go/pkg/mod/github.com/hashicorp/go-sockaddr@v1.0.2/ifaddrs.go:276:13: undefined: NewRouteInfo

Packer Plugin SDK version

Encountered on v0.3.2, but still fails on the main branch.

Operating system and Environment details

go 1.23.1 on AIX 7.3, but reproducible via cross-compilation on Linux

[jtroy]

I've opened a PR with proposed fixes: #263