Protect /mnt/scratch from stale umount on userdebug

On userdebug protect /mnt/scratch. On user builds ensure that
/mnt/scratch is considered a stale mount so it can not be used.
vold runs before ro.debuggable is set, so this must be a compile
time decision.

Minor technical debt cleanup associated with using android::base.

Test: compile
Bug: 109821005
Change-Id: I8efdbedfe850dd24daecf03a37aea61de47edc7d
Merged-In: I8efdbedfe850dd24daecf03a37aea61de47edc7d
diff --git a/Android.bp b/Android.bp
index 1e45727..b115bc1 100644
--- a/Android.bp
+++ b/Android.bp
@@ -139,6 +139,9 @@
                 "libarcobbvolume",
             ],
         },
+        debuggable: {
+            cppflags: ["-D__ANDROID_DEBUGGABLE__"],
+        },
     },
     shared_libs: [
         "android.hardware.health.storage@1.0",