Makefile: rm cgo tag

There is no need to explicitly add `cgo` build tag, it is set by
by go tools if cgo is enabled.

Fixes: 80cf524

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

Makefile

@@ -40,8 +40,8 @@ contrib/cmd/recvtty/recvtty: $(SOURCES)
 	$(GO) build -buildmode=pie $(EXTRA_FLAGS) -ldflags "-X main.gitCommit=${COMMIT} -X main.version=${VERSION} $(EXTRA_LDFLAGS)" -tags "$(BUILDTAGS)" -o contrib/cmd/recvtty/recvtty ./contrib/cmd/recvtty
 
 static: $(SOURCES)
-	CGO_ENABLED=1 $(GO) build $(EXTRA_FLAGS) -tags "$(BUILDTAGS) netgo osusergo cgo static_build" -installsuffix netgo -ldflags "-w -extldflags -static -X main.gitCommit=${COMMIT} -X main.version=${VERSION} $(EXTRA_LDFLAGS)" -o runc .
-	CGO_ENABLED=1 $(GO) build $(EXTRA_FLAGS) -tags "$(BUILDTAGS) netgo osusergo cgo static_build" -installsuffix netgo -ldflags "-w -extldflags -static -X main.gitCommit=${COMMIT} -X main.version=${VERSION} $(EXTRA_LDFLAGS)" -o contrib/cmd/recvtty/recvtty ./contrib/cmd/recvtty
+	CGO_ENABLED=1 $(GO) build $(EXTRA_FLAGS) -tags "$(BUILDTAGS) netgo osusergo static_build" -installsuffix netgo -ldflags "-w -extldflags -static -X main.gitCommit=${COMMIT} -X main.version=${VERSION} $(EXTRA_LDFLAGS)" -o runc .
+	CGO_ENABLED=1 $(GO) build $(EXTRA_FLAGS) -tags "$(BUILDTAGS) netgo osusergo static_build" -installsuffix netgo -ldflags "-w -extldflags -static -X main.gitCommit=${COMMIT} -X main.version=${VERSION} $(EXTRA_LDFLAGS)" -o contrib/cmd/recvtty/recvtty ./contrib/cmd/recvtty
 
 release:
 	script/release.sh -r release/$(VERSION) -v $(VERSION)