Summary: This patch adds new logic to create the necessary tool chains to support offloading for OpenMP. The OpenMP related options are checked and the tool chains created accordingly. Diagnostics are emitted in case the options are illegal or express unknown targets.
Reviewers: echristo, tra, jlebar, rsmith, ABataev, hfinkel
Subscribers: whchung, mkuron, mehdi_amini, cfe-commits, Hahnfeld, arpith-jacob, carlo.bertolli, caomhin
Differential Revision: https://reviews.llvm.org/D21843
llvm-svn: 285311
