Revert "Revert "Test for dangling rules in make checkbuild""

This reverts commit fb941913a3.

Reapplies I4933187e8b72f2ef0c32d18ffea756e2c6fa417c with fixes
to disable the check for mac builds, where many modules are
disabled and the check is just going to cause more problems.

Test: m checkbuild
Change-Id: If6712c90ececd5d015fcdcdeefe0c3d4f5590711

cmd/soong_ui/main.go

@@ -114,7 +114,11 @@ func main() {
 	} else if os.Args[1] == "--dumpvars-mode" {
 		dumpVars(buildCtx, config, os.Args[2:])
 	} else {
-		build.Build(buildCtx, config, build.BuildAll)
+		toBuild := build.BuildAll
+		if config.Checkbuild() {
+			toBuild |= build.RunBuildTests
+		}
+		build.Build(buildCtx, config, toBuild)
 	}
 }