Dalvik: Better compatibility with different compilers

This fixes building with clang, and possibly future versions of gcc:
- Don't error out on unused functions generated by gen-mterp.py
  even when we're using -Werror
- Eliminate some dead code (Word/kWordSize definition) clang warns about
- Add a return statement to a switch path causing a possible code path
  with uninitialized variables (if the compiler doesn't know what
  dvmAbort() is)
- Initialize a variable

Change-Id: I9a3c0a1ad4dce10445e2251e491f18511413ca50
Signed-off-by: Bernhard Rosenkränzer <Bernhard.Rosenkranzer@linaro.org>
Add -Wno-unused-but-set-variable to the Dalvik project.

This is to meet long term goal that we don't suppress any warnings in
the global makefile.

BUG: 10495043
Change-Id: I1eece42a9f2c43b614cfbeb1397c8071fb3db04a
(cherry picked from commit 0c4625a4e1464544625723b013b3febb1cc9359e)
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/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>
Added missing <include sys/resource.h> for gcc-4.7.1

Patch Set 2: Added gcc version check as suggested by jeagoss

Change-Id: I7743d5fab8d026e12ad9e9ef4d4fbabe0a9bded7
We use gcc 4.8 for the host not 4.7