Lint on pkg/* packages

- pkg/useragent
- pkg/units
- pkg/ulimit
- pkg/truncindex
- pkg/timeoutconn
- pkg/term
- pkg/tarsum
- pkg/tailfile
- pkg/systemd
- pkg/stringutils
- pkg/stringid
- pkg/streamformatter
- pkg/sockets
- pkg/signal
- pkg/proxy
- pkg/progressreader
- pkg/pools
- pkg/plugins
- pkg/pidfile
- pkg/parsers
- pkg/parsers/filters
- pkg/parsers/kernel
- pkg/parsers/operatingsystem

Signed-off-by: Vincent Demeester <vincent@sbr.pm>

signal/signal_unix.go

@@ -8,5 +8,9 @@ import (
 
 // Signals used in api/client (no windows equivalent, use
 // invalid signals so they don't get handled)
+
+// SIGCHLD is a signal sent to a process when a child process terminates, is interrupted, or resumes after being interrupted.
 const SIGCHLD = syscall.SIGCHLD
+
+// SIGWINCH is a signal sent to a process when its controlling terminal changes its size
 const SIGWINCH = syscall.SIGWINCH