libutils: turn on -Werror

- Deal with some -Wunused issues
- Override PRI macros (windows)
- Revert use of PRI macros on off64_t (linux)
- Deal with a gnu++11 complaince issue

Change-Id: Ie66751293bd84477a5a6dfd8a57e700a16e36964
diff --git a/libutils/Timers.cpp b/libutils/Timers.cpp
index a431e92..4687d4d 100644
--- a/libutils/Timers.cpp
+++ b/libutils/Timers.cpp
@@ -32,9 +32,9 @@
 #include <windows.h>
 #endif
 
+#if defined(HAVE_ANDROID_OS)
 nsecs_t systemTime(int clock)
 {
-#if defined(HAVE_ANDROID_OS)
     static const clockid_t clocks[] = {
             CLOCK_REALTIME,
             CLOCK_MONOTONIC,
@@ -46,7 +46,10 @@
     t.tv_sec = t.tv_nsec = 0;
     clock_gettime(clocks[clock], &t);
     return nsecs_t(t.tv_sec)*1000000000LL + t.tv_nsec;
+}
 #else
+nsecs_t systemTime(int /*clock*/)
+{
     // Clock support varies widely across hosts. Mac OS doesn't support
     // posix clocks, older glibcs don't support CLOCK_BOOTTIME and Windows
     // is windows.
@@ -54,8 +57,8 @@
     t.tv_sec = t.tv_usec = 0;
     gettimeofday(&t, NULL);
     return nsecs_t(t.tv_sec)*1000000000LL + nsecs_t(t.tv_usec)*1000LL;
-#endif
 }
+#endif
 
 int toMillisecondTimeoutDelay(nsecs_t referenceTime, nsecs_t timeoutTime)
 {