Prevent support libraries from compiling into Gitea (#10964)

* Prevent support libraries from compiling into Gitea

* Fix tag position

* Fix golangci-lint errors

* Refactor to make it work

Co-authored-by: Guillermo Prandi <guillep2k@users.noreply.github.com>

build.go

@@ -0,0 +1,26 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+//+build vendor
+
+package main
+
+// Libraries that are included to vendor utilities used during build.
+// These libraries will not be included in a normal compilation.
+
+import (
+	// for lint
+	_ "github.com/BurntSushi/toml"
+	_ "github.com/mgechev/dots"
+	_ "github.com/mgechev/revive/formatter"
+	_ "github.com/mgechev/revive/lint"
+	_ "github.com/mgechev/revive/rule"
+	_ "github.com/mitchellh/go-homedir"
+
+	// for embed
+	_ "github.com/shurcooL/vfsgen"
+
+	// for cover merge
+	_ "golang.org/x/tools/cover"
+)