This adds extension detection for lower-case ".s" assembly files (used in NSPR) in addition to the existing handling of uppercase ".S" ones.
Minor fixes for build files for Mac for dependencies and files.
Proper handling of USE_NSS and addition of USE_OPENSSL_CERTS that match the GYP build.
R=rsleevi@chromium.org
Review URL: https://codereview.chromium.org/242173002
git-svn-id: http://src.chromium.org/svn/trunk/src/build@265064 4ff67af0-8c30-449e-8e8b-ad334ec8d88c