Revert "Test for dangling rules in make checkbuild"

This reverts commit 7709a057706b478c9687f1facaca115cb61cb169.

Reason for revert: Broke mac checkbuilds

Change-Id: If71ec9198ca8943d90ce9d5e3a277faf239e38a5
diff --git a/ui/build/config.go b/ui/build/config.go
index 99ae2da..940bb2f 100644
--- a/ui/build/config.go
+++ b/ui/build/config.go
@@ -34,12 +34,11 @@
 	environ   *Environment
 
 	// From the arguments
-	parallel   int
-	keepGoing  int
-	verbose    bool
-	checkbuild bool
-	dist       bool
-	skipMake   bool
+	parallel  int
+	keepGoing int
+	verbose   bool
+	dist      bool
+	skipMake  bool
 
 	// From the product config
 	katiArgs     []string
@@ -207,8 +206,6 @@
 		} else {
 			if arg == "dist" {
 				c.dist = true
-			} else if arg == "checkbuild" {
-				c.checkbuild = true
 			}
 			c.arguments = append(c.arguments, arg)
 		}
@@ -316,12 +313,6 @@
 	panic("SetKatiSuffix has not been called")
 }
 
-// Checkbuild returns true if "checkbuild" was one of the build goals, which means that the
-// user is interested in additional checks at the expense of build time.
-func (c *configImpl) Checkbuild() bool {
-	return c.checkbuild
-}
-
 func (c *configImpl) Dist() bool {
 	return c.dist
 }