Conditionally use bootstrap loader in pnacl driver runs of sel_ldr
Conditionally use bootstrap loader in pnacl driver runs of sel_ldr

Using the bootstrap loader will soon be the default on Linux.
When that comes into effect, it will need a pnacl toolchain that
is set up to use the bootstrap loader.  So we need that built now.

BUG= none
TEST= trybots

R=pdox@google.com

Review URL: http://codereview.chromium.org/8726015

git-svn-id: 721b910a23eff8a86f00c8fd261a7587cddf18f8@7295 fcba33aa-ac0c-11dd-b9e7-8d5594d729c2

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