Warnings fixed include the following.
- Several cases where macros (|LOG| and |ALOGE|) were redefined. I just did a
simple #undef to fix these.
- In GonkMemoryPressureMonitoring.cpp, "the address of NuwaMarkCurrentThread
will never be NULL".
- In OrientationObserver.cpp, several signed/unsigned comparison warnings.
- Several warnings about variables that are unused or set but not used:
in InputDispatcher.cpp, InputReader.cpp.
Also in SpriteController, where several loops were all but empty if
HAVE_ANDROID_OS is undefined; for these I moved the HAVE_ANDROID_OS check
outside the loop.
The patch also disallows the introduction of new warnings by removing the
ALLOW_COMPILER_WARNINGS flag.
