toolchain_build: Build GCC target libraries with -mtp=soft
toolchain_build: Build GCC target libraries with -mtp=soft

For the libstdc++.a in the toolchain to be usable to build an IRT,
it must use -mtp=soft.

BUG= http://code.google.com/p/nativeclient/issues/detail?id=3351
TEST= trybots

R=sbc@chromium.org,bradnelson@google.com

Review URL: https://codereview.chromium.org/13094011

git-svn-id: 721b910a23eff8a86f00c8fd261a7587cddf18f8@11066 fcba33aa-ac0c-11dd-b9e7-8d5594d729c2

sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client