Disable DalvikVM GC logcat spam

Dalvik logs everytime a garbage collection is run. Disabled to remove
clutter from logcat. Can be renabled by #defining DEBUG.

Change-Id: I57a461857f8d0ecbf223f3c18187f62095adb5b4

Made minor changes to https://github.com/ParanoidAndroid/android_dalvik/commit/36ffd053900b25f46b6260f951852abbc49d5730

Re-enable GC logging by setting DALVIK_LOG_GC
dalvik: Fix various compile failures with gcc 4.6

This fixes numerous compile errors with gcc 4.6, and combinations
of -DNDEBUG, -DLOG_NDEBUG resulting in variables being defined but
not used - resulting in a compiler warning (or build breakage
with -Werror).

Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>

dalvik: Fix aliasing violation

Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>

dalvik/libdex: Change to -O2 if we're building with -O3

This is a workaround for an apparent gcc bug.
https://bugs.launchpad.net/linaro-android/+bug/948255

Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>

dalvik: Fix build with ISO C++11

Fixes some confusion between jchar and the new char16_t

Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>
dalvik/libdex: Don't reduce optimization level to -O2

Don't reduce optimization level to -O2: It's sufficient to disable
function inlining

Change-Id: Ie6d9978cf0bf0e49cfa296c09c4eba913f22c303
Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>