Expose GOBIN in the Makefile.

This allows for builds that make use of multiple local toolchains.

Signed-off-by: Aaron Jacobs <[email protected]>

Makefile

@@ -1,11 +1,12 @@
+GOBIN = go
 CGO_ENABLED = 0
 # Strip binaries by default to make them smaller.
 GO_LDFLAGS = -s -w
 # Using the 'netgo' tag opts into the native implementation and allows for
 # static binaries.
 GO_BUILD_ARGS = -v -tags "netgo" -trimpath
 
-GOPATH = `go env GOPATH`
+GOPATH = `$(GOBIN) env GOPATH`
 ADDLICENSE = $(GOPATH)/bin/addlicense
 ADDLICENSE_ARGS = -v -s=only -l=apache -c "RStudio, PBC" -ignore 'coverage*' -ignore '.github/**' -ignore '.goreleaser.yaml'
 NOTICETOOL = $(GOPATH)/bin/go-licence-detector
@@ -14,7 +15,7 @@ all: rskey
 
 .PHONY: rskey
 rskey:
-	GO111MODULE=on CGO_ENABLED=$(CGO_ENABLED) go build \
+	GO111MODULE=on CGO_ENABLED=$(CGO_ENABLED) $(GOBIN) build \
 		-ldflags="$(GO_LDFLAGS)" $(GO_BUILD_ARGS) -o $@ ./$<
 
 .PHONY: static-build
@@ -25,18 +26,18 @@ check: fmt vet
 
 .PHONY: test
 test:
-	GO111MODULE=on go test ./... $(GO_BUILD_ARGS) -coverprofile coverage.out
-	go tool cover -html=coverage.out -o coverage.html
-	GO111MODULE=on go test ./... $(GO_BUILD_ARGS) -tags "fips" -coverprofile coverage-fips.out
-	go tool cover -html=coverage-fips.out -o coverage-fips.html
+	GO111MODULE=on $(GOBIN) test ./... $(GO_BUILD_ARGS) -coverprofile coverage.out
+	$(GOBIN) tool cover -html=coverage.out -o coverage.html
+	GO111MODULE=on $(GOBIN) test ./... $(GO_BUILD_ARGS) -tags "fips" -coverprofile coverage-fips.out
+	$(GOBIN) tool cover -html=coverage-fips.out -o coverage-fips.html
 
 .PHONY: fmt
 fmt:
-	GO111MODULE=on go fmt ./...
+	GO111MODULE=on $(GOBIN) fmt ./...
 
 .PHONY: vet
 vet:
-	GO111MODULE=on go vet ./...
+	GO111MODULE=on $(GOBIN) vet ./...
 
 .PHONY: check-license
 check-license: