toolbox: prevent executing tools

Change-Id: Id3d2b15d6c0dad346282e59eb2f173da2776a905
diff --git a/toolbox/Android.mk b/toolbox/Android.mk
index b8f4d2e..bf77ba2 100644
--- a/toolbox/Android.mk
+++ b/toolbox/Android.mk
@@ -47,14 +47,18 @@
             $(if $(filter $(PLATFORM_SDK_VERSION), 23 24), du)
 
         OUR_TOOLS := \
-            $(if $(shell test $(PLATFORM_SDK_VERSION) -lt 26; iftop),) \
-            $(if $(shell test $(PLATFORM_SDK_VERSION) -lt 26; ioctl),) \
-            $(if $(shell test $(PLATFORM_SDK_VERSION) -lt 26; nandread),) \
-            newfs_msdos \
-            $(if $(shell test $(PLATFORM_SDK_VERSION) -lt 26; prlimit),) \
-            $(if $(shell test $(PLATFORM_SDK_VERSION) -lt 26; sendevent),) \
-            $(if $(shell test $(PLATFORM_SDK_VERSION) -lt 26; start),) \
-            $(if $(shell test $(PLATFORM_SDK_VERSION) -lt 26; stop),) \
+            newfs_msdos
+
+        ifeq ($(shell test $(PLATFORM_SDK_VERSION) -lt 26; echo $$?),0)
+            OUR_TOOLS += \
+                iftop \
+                ioctl \
+                nandread \
+                prlimit \
+                sendevent \
+                start \
+                stop
+        endif
 
         ifneq (,$(filter $(PLATFORM_SDK_VERSION), 23))
             BSD_TOOLS += \