Fix memtrack_helper for newer versions Android.

tools/android/memtrack_helper/memtrack_helper.h

Index: tools/android/memtrack_helper/memtrack_helper.h
diff --git a/tools/android/memtrack_helper/memtrack_helper.h b/tools/android/memtrack_helper/memtrack_helper.h
index df349c3c3ed6e9e05a5ee6d6c66d3d2f24480502..9a2de37819060c0b6a96f7e1880ac2f8753b224d 100644
--- a/tools/android/memtrack_helper/memtrack_helper.h
+++ b/tools/android/memtrack_helper/memtrack_helper.h
@@ -15,9 +15,11 @@
 #include <sys/socket.h>
 #include <sys/un.h>
 
+static const char* const kLogTag = "memtrack_helper";
+
 static inline void exit_with_failure(const char* reason) {
   perror(reason);
-  __android_log_write(ANDROID_LOG_ERROR, "memtrack_helper", reason);
+  __android_log_write(ANDROID_LOG_ERROR, kLogTag, reason);
   exit(EXIT_FAILURE);
 }