makefile: place phony markers after targets (#4408)

The .PHONY targets in the Makefile are usually placed far away from the actual targets, and thus aren't always updated. Placing the .PHONY targets right next to the targets they cover make them more visible and thus more likely to be updated when necessary.

tools.mk

@@ -51,25 +51,31 @@ PROTOBUF     	= $(TOOLS_DESTDIR)/protoc
 GOODMAN 			= $(TOOLS_DESTDIR)/goodman
 
 all: tools
+.PHONY: all
 
 tools: certstrap protobuf goodman
+.PHONY: tools
 
 check: check_tools
+.PHONY: check
 
 check_tools:
 	@# https://stackoverflow.com/a/25668869
 	@echo "Found tools: $(foreach tool,$(notdir $(GOTOOLS)),\
         $(if $(shell which $(tool)),$(tool),$(error "No $(tool) in PATH")))"
+.PHONY: check_tools
 
 certstrap: $(CERTSTRAP)
 $(CERTSTRAP):
 	@echo "Get Certstrap"
 	@go get github.com/square/certstrap@v1.2.0
+.PHONY: certstrap
 
 protobuf: $(PROTOBUF)
 $(PROTOBUF):
 	@echo "Get GoGo Protobuf"
 	@go get github.com/gogo/protobuf/protoc-gen-gogo@v1.3.1
+.PHONY: protobuf
 
 buf: protoc-gen-buf-check-breaking protoc-gen-buf-check-lint
 	@echo "Installing buf..."
@@ -77,6 +83,7 @@ buf: protoc-gen-buf-check-breaking protoc-gen-buf-check-lint
     "https://github.com/bufbuild/buf/releases/download/v${BUF_VERSION}/buf-${UNAME_S}-${UNAME_M}" \
     -o "${BIN}/buf" && \
 	chmod +x "${BIN}/buf"
+.PHONY: buf
 
 protoc-gen-buf-check-breaking:
 	@echo "Installing protoc-gen-buf-check-breaking..."
@@ -91,17 +98,20 @@ protoc-gen-buf-check-lint:
     "https://github.com/bufbuild/buf/releases/download/v${BUF_VERSION}/protoc-gen-buf-check-lint-${UNAME_S}-${UNAME_M}" \
     -o "${BIN}/protoc-gen-buf-check-lint" && \
 	chmod +x "${BIN}/protoc-gen-buf-check-lint"
+.PHONY: protoc-gen-buf-check-lint
 
 goodman: $(GOODMAN)
 $(GOODMAN):
 	@echo "Get Goodman"
 	@go get github.com/snikch/goodman/cmd/goodman@10e37e294daa3c9a90abded60ff9924bafab3888
+.PHONY: goodman
 
 tools-clean:
 	rm -f $(CERTSTRAP) $(PROTOBUF) $(GOX) $(GOODMAN)
 	rm -f tools-stamp
 	rm -rf /usr/local/include/google/protobuf
 	rm -f /usr/local/bin/protoc
+.PHONY: tooks-clean
 
 ###
 # Non Go tools
@@ -127,5 +137,4 @@ protoc:
 	@unzip -o $(PROTOC_ZIP) -d /usr/local bin/protoc
 	@unzip -o $(PROTOC_ZIP) -d /usr/local 'include/*'
 	@rm -f $(PROTOC_ZIP)
-
-.PHONY: all tools tools-clean protoc
+.PHONY: protoc