Linters and cgo support

[ldez]

The list of linters that don't work with cgo:

• exhaustive
• gci
• godot fix: cgo support tetafro/godot#37
• goheader
• gosec
• ineffassign
• nlreturn Nlreturn sees linter error in CGO code without such error ssgreg/nlreturn#4
• testableexamples (import "C" is not allowed inside tests)
• unparam
• unused
• whitespace
• wsl fix: cgo support bombsimon/wsl#157

Please, don't open issues on linter repositories unless you know exactly the reason for cgo limitations.
Each linter has its constraints, and some problems come from golangci-lint.