binary size checking hooks

internal/build/build.go

@@ -1,5 +1,3 @@
-//+build ignore
-
 package main
 
 import (
@@ -40,6 +38,10 @@ func main() {
 			Name:   "toc",
 			Action: TocActionFunc,
 		},
+		{
+			Name:   "check-binary-size",
+			Action: checkBinarySizeActionFunc,
+		},
 	}
 
 	err := app.Run(os.Args)
@@ -178,3 +180,12 @@ func TocActionFunc(c *cli.Context) error {
 
 	return nil
 }
+
+func checkBinarySizeActionFunc(c *cli.Context) (err error) {
+	err = runCmd("git", "diff", "--exit-code")
+	if err != nil {
+		return err
+	}
+
+	return nil
+}