Simplify some old build cruft

Things are a lot easier nowadays!

Author: mhagger

CONTRIBUTING.md

@@ -20,7 +20,7 @@ Please note that this project is released with a [Contributor Code of Conduct][c
 
 Here are a few things you can do that will increase the likelihood of your pull request being accepted:
 
-- Make sure that your code is formatted correctly: `make gofmt`.
+- Make sure that your code is formatted correctly according to `go fmt`: `go fmt .`.
 - Write tests.
 - Keep your change as focused as possible. If there are multiple changes you would like to make that are not dependent upon each other, consider submitting them as separate pull requests.
 - Write a [good commit message](http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html).

Makefile

@@ -3,7 +3,6 @@ GO111MODULES := 1
 export GO111MODULES
 
 GO := $(CURDIR)/script/go
-GOFMT := $(CURDIR)/script/gofmt
 
 GO_LDFLAGS := -X main.BuildVersion=$(shell git describe --tags --always --dirty || echo unknown)
 GOFLAGS := -ldflags "$(GO_LDFLAGS)"
@@ -12,14 +11,6 @@ ifdef USE_ISATTY
 GOFLAGS := $(GOFLAGS) --tags isatty
 endif
 
-GO_SRCS := $(sort $(shell $(GO) list -f ' \
-	{{$$ip := .Dir}} \
-	{{range .GoFiles     }}{{printf "%s/%s\n" $$ip .}}{{end}} \
-	{{range .CgoFiles    }}{{printf "%s/%s\n" $$ip .}}{{end}} \
-	{{range .TestGoFiles }}{{printf "%s/%s\n" $$ip .}}{{end}} \
-	{{range .XTestGoFiles}}{{printf "%s/%s\n" $$ip .}}{{end}} \
-	' ./...))
-
 .PHONY: all
 all: bin/git-sizer
 
@@ -85,23 +76,6 @@ test: bin/git-sizer gotest
 gotest:
 	$(GO) test -timeout 60s $(GOFLAGS) ./...
 
-.PHONY: gofmt
-gofmt:
-	$(GOFMT) -l -w $(GO_SRCS) | sed -e 's/^/Fixing /'
-
-.PHONY: goimports
-goimports:
-	goimports -l -w -e $(GO_SRCS)
-
-.PHONY: govet
-govet:
-	$(GO) vet ./...
-
 .PHONY: clean
 clean:
 	rm -rf bin
-
-# List all of this project's Go sources:
-.PHONY: srcs
-srcs:
-	@printf "%s\n" $(GO_SRCS)

docs/BUILDING.md

@@ -25,7 +25,7 @@ This procedure is intended for experts and people who want to help develop `git-
         git clone https://github.com/github/git-sizer.git
         cd git-sizer
 
-2.  Install Go if necessary and create and prepare a project-local `GOPATH`:
+2.  Install Go if necessary:
 
         script/bootstrap