Another fix to preserve the current working directory when invoking build.sh.
Another fix to preserve the current working directory when invoking build.sh.

TBR= robertm
Review URL: http://codereview.chromium.org/8587033

git-svn-id: 721b910a23eff8a86f00c8fd261a7587cddf18f8@7213 fcba33aa-ac0c-11dd-b9e7-8d5594d729c2

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