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/include/gui/Sensor.h b/include/gui/Sensor.h
index 59b4d4d..27a215e 100644
--- a/include/gui/Sensor.h
+++ b/include/gui/Sensor.h
@@ -67,12 +67,12 @@
     int32_t getMinDelay() const;
     nsecs_t getMinDelayNs() const;
     int32_t getVersion() const;
-    int32_t getFifoReservedEventCount() const;
-    int32_t getFifoMaxEventCount() const;
+    uint32_t getFifoReservedEventCount() const;
+    uint32_t getFifoMaxEventCount() const;
     const String8& getStringType() const;
     const String8& getRequiredPermission() const;
     int32_t getMaxDelay() const;
-    int32_t getFlags() const;
+    uint32_t getFlags() const;
     bool isWakeUpSensor() const;
     int32_t getReportingMode() const;
 
@@ -93,8 +93,8 @@
     float   mPower;
     int32_t mMinDelay;
     int32_t mVersion;
-    int32_t mFifoReservedEventCount;
-    int32_t mFifoMaxEventCount;
+    uint32_t mFifoReservedEventCount;
+    uint32_t mFifoMaxEventCount;
     String8 mStringType;
     String8 mRequiredPermission;
     int32_t mMaxDelay;