fix: use go:build comments rather than deprecated +build directive and adjust go vet tooling in Makefile (#41)

Author: mac641

Makefile

@@ -31,7 +31,7 @@ test:
 
 .PHONY: lint
 lint:
-	$(GOMODULECMD) tool vet .
+	$(GOMODULECMD) vet ./...
 
 
 IPXE_COMMIT_SHA := $(shell cat ipxe/IPXE_COMMIT_SHA)
@@ -53,4 +53,4 @@ ipxe:
 	mv -f ipxe/ipxe/src/bin/undionly.kpxe ipxe/ipxe/bin/undionly.kpxe
 	mv -f ipxe/ipxe/src/bin-x86_64-efi/ipxe.efi ipxe/ipxe/bin/ipxe-x86_64.efi
 	mv -f ipxe/ipxe/src/bin-i386-efi/ipxe.efi ipxe/ipxe/bin/ipxe-i386.efi
-	(cd ipxe/ipxe/src && make veryclean)
+	(cd ipxe/ipxe/src && make veryclean)

dhcp4/conn_linux.go

@@ -13,7 +13,6 @@
 // limitations under the License.
 
 //go:build linux
-// +build linux
 
 package dhcp4
 

dhcp4/conn_linux_test.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//+build linux
+//go:build linux
 
 package dhcp4
 

dhcp4/conn_unsupported.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//+build !linux
+//go:build !linux
 
 package dhcp4