add staticcheck linter

Makefile

@@ -5,7 +5,7 @@ LDFLAGS := -X github.com/tomcz/openldap_exporter.commit=${GITCOMMIT}
 LDFLAGS := ${LDFLAGS} -X github.com/tomcz/openldap_exporter.tag=${GIT_TAG}
 
 .PHONY: precommit
-precommit: clean format build
+precommit: clean format lint build
 
 .PHONY: commit
 commit: clean
@@ -26,6 +26,14 @@ endif
 	@echo "Running goimports ..."
 	@goimports -w -local github.com/tomcz/openldap_exporter $(shell find . -type f -name '*.go' | grep -v '/vendor/')
 
+.PHONY: lint
+lint:
+ifeq (, $(shell which staticcheck))
+	go install honnef.co/go/tools/cmd/[email protected]
+endif
+	@echo "Running staticcheck ..."
+	@staticcheck $(shell go list ./... | grep -v /vendor/)
+
 compile = GOOS=$1 GOARCH=amd64 go build -ldflags "${LDFLAGS}" -o target/openldap_exporter-$1 ./cmd/openldap_exporter
 
 .PHONY: build