Pull request: all: restore netbsd compat

Updates #3147.

Squashed commit of the following:

commit 4e1bcfd1561f9b927755c5024521d5508ef94b1f
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon May 17 13:17:51 2021 +0300

    all: restore netbsd compat

scripts/make/go-lint.sh

@@ -92,6 +92,7 @@ underscores() {
 	git ls-files '*_*.go' | {
 		grep -F\
 		-e '_big.go'\
+		-e '_bsd.go'\
 		-e '_darwin.go'\
 		-e '_freebsd.go'\
 		-e '_linux.go'\