make: add Makefile

As a preparation to get rid of the clunky to handle goclean.sh, we add a
Makefile that behaves in mostly the same way as does lnd's Makefile.

Makefile

@@ -0,0 +1,132 @@
+PKG := github.com/btcsuite/btcwallet
+
+GOVERALLS_PKG := github.com/mattn/goveralls
+LINT_PKG := github.com/golangci/golangci-lint/cmd/golangci-lint
+GOACC_PKG := github.com/ory/go-acc
+GOIMPORTS_PKG := golang.org/x/tools/cmd/goimports
+
+GO_BIN := ${GOPATH}/bin
+GOVERALLS_BIN := $(GO_BIN)/goveralls
+LINT_BIN := $(GO_BIN)/golangci-lint
+GOACC_BIN := $(GO_BIN)/go-acc
+
+LINT_COMMIT := v1.18.0
+GOACC_COMMIT := ddc355013f90fea78d83d3a6c71f1d37ac07ecd5
+
+DEPGET := cd /tmp && GO111MODULE=on go get -v
+GOBUILD := GO111MODULE=on go build -v
+GOINSTALL := GO111MODULE=on go install -v
+GOTEST := GO111MODULE=on go test 
+
+GOLIST := go list -deps $(PKG)/... | grep '$(PKG)'
+GOLIST_COVER := $$(go list -deps $(PKG)/... | grep '$(PKG)')
+GOFILES_NOVENDOR = $(shell find . -type f -name '*.go' -not -path "./vendor/*")
+
+RM := rm -f
+CP := cp
+MAKE := make
+XARGS := xargs -L 1
+
+# Linting uses a lot of memory, so keep it under control by limiting the number
+# of workers if requested.
+ifneq ($(workers),)
+LINT_WORKERS = --concurrency=$(workers)
+endif
+
+LINT = $(LINT_BIN) run -v $(LINT_WORKERS)
+
+GREEN := "\\033[0;32m"
+NC := "\\033[0m"
+define print
+	echo $(GREEN)$1$(NC)
+endef
+
+default: build
+
+all: build check
+
+# ============
+# DEPENDENCIES
+# ============
+
+$(GOVERALLS_BIN):
+	@$(call print, "Fetching goveralls.")
+	go get -u $(GOVERALLS_PKG)
+
+$(LINT_BIN):
+	@$(call print, "Fetching linter")
+	$(DEPGET) $(LINT_PKG)@$(LINT_COMMIT)
+
+$(GOACC_BIN):
+	@$(call print, "Fetching go-acc")
+	$(DEPGET) $(GOACC_PKG)@$(GOACC_COMMIT)
+
+goimports:
+	@$(call print, "Installing goimports.")
+	$(DEPGET) $(GOIMPORTS_PKG)
+
+# ============
+# INSTALLATION
+# ============
+
+build:
+	@$(call print, "Compiling btcwallet.")
+	$(GOBUILD) $(PKG)/...
+
+install:
+	@$(call print, "Installing btcwallet.")
+	$(GOINSTALL) $(PKG)
+	$(GOINSTALL) $(PKG)/cmd/dropwtxmgr
+	$(GOINSTALL) $(PKG)/cmd/sweepaccount
+
+# =======
+# TESTING
+# =======
+
+check: unit
+
+unit:
+	@$(call print, "Running unit tests.")
+	$(GOLIST) | $(XARGS) env $(GOTEST)
+
+unit-cover: $(GOACC_BIN)
+	@$(call print, "Running unit coverage tests.")
+	$(GOACC_BIN) $(GOLIST_COVER)
+
+unit-race:
+	@$(call print, "Running unit race tests.")
+	env CGO_ENABLED=1 GORACE="history_size=7 halt_on_errors=1" $(GOLIST) | $(XARGS) env $(GOTEST) -race
+
+goveralls: $(GOVERALLS_BIN)
+	@$(call print, "Sending coverage report.")
+	$(GOVERALLS_BIN) -coverprofile=coverage.txt -service=travis-ci
+
+# =========
+# UTILITIES
+# =========
+
+fmt: goimports
+	@$(call print, "Fixing imports.")
+	goimports -w $(GOFILES_NOVENDOR)
+	@$(call print, "Formatting source.")
+	gofmt -l -w -s $(GOFILES_NOVENDOR)
+
+lint: $(LINT_BIN)
+	@$(call print, "Linting source.")
+	$(LINT)
+
+clean:
+	@$(call print, "Cleaning source.$(NC)")
+	$(RM) coverage.txt
+
+.PHONY: all \
+	default \
+	build \
+	check \
+	unit \
+	unit-cover \
+	unit-race \
+	goveralls \
+	fmt \
+	lint \
+	clean