Build sandboxed llc and ld w/ -ffunction-sections and --gc-sections.
Build sandboxed llc and ld w/ -ffunction-sections and --gc-sections.

This will make the nexes smaller.  When we remove
--export-dynamic without triggering ARM bugs, we can rely
on the optimizer to reduce the size of the nexes even more.

For now, this reduces LLC by 1MB per architecture and it
also reduces gold size by a tiny bit too.

before:
RESULT llc_armv7_size: total= 16801608 bytes
RESULT llc_i686_size: total= 16489508 bytes
RESULT llc_x86_64_size: total= 17229352 bytes
RESULT ld_armv7_size: total= 2786976 bytes
RESULT ld_i686_size: total= 2503688 bytes
RESULT ld_x86_64_size: total= 2873508 bytes

after:
RESULT llc_armv7_size: total= 15665888 bytes
RESULT llc_i686_size: total= 15373968 bytes
RESULT llc_x86_64_size: total= 16060772 bytes
RESULT ld_armv7_size: total= 2771316 bytes
RESULT ld_i686_size: total= 2488984 bytes
RESULT ld_x86_64_size: total= 2858368 bytes

Without --export-dynamic, in a 2-week old tryjob I had:

RESULT llc_i686_size: total= 13569584 bytes

even without -ffunction-sections and --gc-sections:

http://build.chromium.org/p/tryserver.nacl/builders/nacl-toolchain-linux-pnacl-x86_64/builds/165/steps/compile_translator/logs/stdio

BUG= http://code.google.com/p/nativeclient/issues/detail?id=1222

Will need to remove these flags to test:

BUG= http://code.google.com/p/nativeclient/issues/detail?id=1591

Review URL: https://codereview.chromium.org/11234014

git-svn-id: 721b910a23eff8a86f00c8fd261a7587cddf18f8@10063 fcba33aa-ac0c-11dd-b9e7-8d5594d729c2

sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,nacl-webkit/native_client,sbc100/native_client,nacl-webkit/native_client,nacl-webkit/native_client,nacl-webkit/native_client,sbc100/native_client,nacl-webkit/native_client