libgui: Enable -Weverything and -Werror

Enables -Weverything and -Werror, with just a few exceptions for
warnings we can't (or shouldn't need to) work around.

Change-Id: I034abec27bf4020d84af60d7acc1939c59986dd6
diff --git a/libs/gui/SensorEventQueue.cpp b/libs/gui/SensorEventQueue.cpp
index 6f5f204..76ae470 100644
--- a/libs/gui/SensorEventQueue.cpp
+++ b/libs/gui/SensorEventQueue.cpp
@@ -16,6 +16,7 @@
 
 #define LOG_TAG "Sensors"
 
+#include <algorithm>
 #include <stdint.h>
 #include <sys/types.h>
 #include <sys/socket.h>
@@ -31,6 +32,8 @@
 
 #include <android/sensor.h>
 
+using std::min;
+
 // ----------------------------------------------------------------------------
 namespace android {
 // ----------------------------------------------------------------------------
@@ -68,14 +71,14 @@
         if (err < 0) {
             return err;
         }
-        mAvailable = err;
+        mAvailable = static_cast<size_t>(err);
         mConsumed = 0;
     }
-    size_t count = numEvents < mAvailable ? numEvents : mAvailable;
-    memcpy(events, mRecBuffer + mConsumed, count*sizeof(ASensorEvent));
+    size_t count = min(numEvents, mAvailable);
+    memcpy(events, mRecBuffer + mConsumed, count * sizeof(ASensorEvent));
     mAvailable -= count;
     mConsumed += count;
-    return count;
+    return static_cast<ssize_t>(count);
 }
 
 sp<Looper> SensorEventQueue::getLooper() const