libdvm should block SIGPIPE like the RI does.

Normally AndroidRuntime.cpp patches over this lapse, but that means
that tests run by vogar or any other kind of "bare" VM doesn't handle
SIGPIPE correctly. I'll remove the workaround from AndroidRuntime.cpp.

(cherry-pick of 8723464b85290c1b348bf3e29d06e6d0a291fd4c.)

Bug: 10211309
Change-Id: I5ecb9cbb80b174590694a8837e71507b595ef6de
Minor code cleanup to address warnings found by Clang.

cherry-picked from internal Android branch
55617c82a73d84ff3695bdd5526159448262d009

Change-Id: I0f78ca6b8293c13d7dbb535556543f6ea9f4dd45
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)