ci(makefile): add dep option; use timestamp for fake gopath suffix

.gitignore

@@ -23,4 +23,6 @@ package.json
 /node_modules/
 
 /.vscode/
-/vendor/
+/vendor/
+
+.fake_gopath_suffix

Makefile

@@ -1,30 +1,37 @@
 PACKAGE = github.com/vechain/thor
 
-GIT_COMMIT = $(shell git --no-pager log --pretty="%h" -n 1)
-FAKE_GOPATH = /tmp/thor-build-$(GIT_COMMIT)
+FAKE_GOPATH_SUFFIX = $(shell [ -e ".fake_gopath_suffix" ] || date +%s > .fake_gopath_suffix; cat .fake_gopath_suffix)
+FAKE_GOPATH = /tmp/thor-build-$(FAKE_GOPATH_SUFFIX)
 export GOPATH = $(FAKE_GOPATH)
 
 SRC_BASE = $(FAKE_GOPATH)/src/$(PACKAGE)
 
+GIT_COMMIT = $(shell git --no-pager log --pretty="%h" -n 1)
+GIT_TAG = $(shell git tag -l --points-at HEAD)
+THOR_VERSION = $(shell cat cmd/thor/VERSION)
+DISCO_VERSION = $(shell cat cmd/disco/VERSION)
 
-THOR_VERSION = `cat cmd/thor/VERSION`
-THOR_TAG = `git tag -l --points-at HEAD`
-DISCO_VERSION = `cat cmd/disco/VERSION`
-DISCO_TAG = `git tag -l --points-at HEAD`
-PACKAGES = `cd $(SRC_BASE) && go list ./... | grep -v '/vendor/'`
+PACKAGES = $(shell cd $(SRC_BASE) && go list ./... | grep -v '/vendor/')
 
 .PHONY: thor disco all clean test
 
 thor: |$(SRC_BASE)
 	@echo "building $@..."
-	@cd $(SRC_BASE) && go build -v -i -o $(CURDIR)/bin/$@ -ldflags "-X main.version=$(THOR_VERSION) -X main.gitCommit=$(GIT_COMMIT) -X main.gitTag=$(THOR_TAG)" ./cmd/thor
+	@cd $(SRC_BASE) && go build -v -i -o $(CURDIR)/bin/$@ -ldflags "-X main.version=$(THOR_VERSION) -X main.gitCommit=$(GIT_COMMIT) -X main.gitTag=$(GIT_TAG)" ./cmd/thor
 	@echo "done. executable created at 'bin/$@'"
 
 disco: |$(SRC_BASE)
 	@echo "building $@..."
-	@cd $(SRC_BASE) && go build -v -i -o $(CURDIR)/bin/$@ -ldflags "-X main.version=$(DISCO_VERSION) -X main.gitCommit=$(GIT_COMMIT) -X main.gitTag=$(DISCO_TAG)" ./cmd/disco
+	@cd $(SRC_BASE) && go build -v -i -o $(CURDIR)/bin/$@ -ldflags "-X main.version=$(DISCO_VERSION) -X main.gitCommit=$(GIT_COMMIT) -X main.gitTag=$(GIT_TAG)" ./cmd/disco
 	@echo "done. executable created at 'bin/$@'"
 
+dep:
+ifeq ($(shell command -v dep 2> /dev/null),)
+	@git submodule update --init
+else
+	@dep ensure	
+endif
+
 $(SRC_BASE):
 	@mkdir -p $(dir $@)
 	@ln -sf $(CURDIR) $@