build: Build mgmt on any go file change

Prior to this commit, running make would only rebuild mgmt when
main.go was changed. It means that make clean build was needed.

With this commit, any go file change in this directory will
trigger a new compilation.

Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>

Makefile

@@ -19,6 +19,7 @@ SHELL = /usr/bin/env bash
 .PHONY: all art cleanart version program path deps run race generate build clean test gofmt yamlfmt format docs rpmbuild mkdirs rpm srpm spec tar upload upload-sources upload-srpms upload-rpms copr
 .SILENT: clean
 
+GO_FILES := $(shell find . -name '*.go')
 SVERSION := $(or $(SVERSION),$(shell git describe --match '[0-9]*\.[0-9]*\.[0-9]*' --tags --dirty --always))
 VERSION := $(or $(VERSION),$(shell git describe --match '[0-9]*\.[0-9]*\.[0-9]*' --tags --abbrev=0))
 PROGRAM := $(shell echo $(notdir $(CURDIR)) | cut -f1 -d"-")
@@ -106,7 +107,7 @@ generate:
 
 build: $(PROGRAM)
 
-$(PROGRAM): main.go
+$(PROGRAM): $(GO_FILES)
 	@echo "Building: $(PROGRAM), version: $(SVERSION)..."
 ifneq ($(OLDGOLANG),)
 	@# avoid equals sign in old golang versions eg in: -X foo=bar
@@ -115,7 +116,7 @@ else
 	time go build -i -ldflags "-X main.program=$(PROGRAM) -X main.version=$(SVERSION)" -o $(PROGRAM) $(BUILD_FLAGS);
 endif
 
-$(PROGRAM).static: main.go
+$(PROGRAM).static: $(GO_FILES)
 	@echo "Building: $(PROGRAM).static, version: $(SVERSION)..."
 	go generate
 ifneq ($(OLDGOLANG),)